joining us here at 5:00 lester holt is next. >> we're back here at 6:00. on this thursday night, under the radar. the feds scrambling to answer how that postal worker landed on the capitol lawn, flying 50 miles without being detected, exposing a major threat. home grown terror. the american charged tonight. investigators say he went to syria to train with isis, then came home with plans to attack. the tic call for help from the airport worker trapped in midair inside the cargo hold, pleading with a 911 operator from his cell phone. and snoring risk. the new warning tonight about sleep apnea and snoring, the potential connection to memory loss and dementia, and what you can do to fight it. "nightly news" begins right now. from nbc news world headquarters in new york, this is "nbc

nightly news." reporting tonight, lester holt. good evening. that bizarre aerial stunt in washington, d.c., is still rattling nerves today with the question what if on a lot of minds. we're talking about that copter that flew undetected to the u.s. capitol yesterday through some of the most restricted air space in the country. it was piloted by a florida mailman with a political message but who, as far as we know, had no intent to do harm. but what if someone else was at the controls, someone with deadly intent? tonight we're not the only ones asking, and some of the answers we're getting aren't totally reassuring. our national correspondent peter alexander is on the story for us. >> reporter: first, the stunt, now the scrutiny. >> this is not good, people. >> reporter: this unprecedented act of civil disobedience is today refocusing new attention on a longstanding security vulnerability, the threat posed by low-flying lightweight aircraft. secretary of homeland security jeh johnson.

>> this individual apparently literally flew in under the radar, literally. >> reporter: federal authorities today charged 61-year-old florida mailman doug hughes with violating restricted air space and operating an unregistered aircraft. the maximum penalty one and three years each. a judge released hughes and ordered him to stay out of washington until a hearing next month. hughes told the "tampa bay times" last year he wanted to deliver a message to washington to end big money in politics. >> i'd rather die in the flight than live to be 80 years old and see this country fall. >> reporter: instead, his flight sparked a discussion about security. >> how did it happen? how did the helicopter get through? why weren't there alarm bells that went off? why wasn't it intercepted? >> reporter: this was basically the gyrocopter's flight path as it rounded the washington monument heading straight down the national mall for the capitol building. but had he taken a left turn, the pilot would have had a straight shot for the white house. the nation's capital is teeming with law enforcement, secret service, capitol

police, park police. but none stopped what hughes once described as a flying bicycle. who should be in charge of that restricted air space ultimately? >> we've got a well-coordinated federal response to dealing with issues of those who penetrate the restricted air space. without permission. >> reporter: secret service, military, capitol police. >> a well-coordinated response. >> reporter: the u.s. no longer flies fighter jets 24/7 over d.c. like after 9/11. but a senior military official tells nbc's jim miklaszewski even if jets were already in the air, they would have been ineffective against such a small, slow-flying target. after getting a head's up from hughes "tampa bay times" reporter ben montgomery drove to washington to watch, but the secret service says the paper never alerted authorities. >> that's not my job to pull the plug on somebody doing something like this. >> reporter: today the white house even weighed in. press secretary josh earnest saying this episode has prompted security teams to re-evaluate their security measures throughout the nation's capital.

lester? >> all right, peter alexander tonight, thank you. we've reported a lot of stories lately about americans allegedly trying to make their way to syria to join isis, but tonight an ohio man is accused of not only going there and receiving terrorist training but also coming back to the states with plans to carry out an attack right here at home. nbc's justice correspondent pete williams has details. >> reporter: american officials say today's charges reflect a growing fear people in the u.s. going to syria, getting training, then coming back as committed terrorists. prosecutors today accused a 23-year-old somali-born man from columbus, ohio. abdirahman sheik mohamud of buying a one-way ticket to athens greece last year getting to istanbul and making his way into syria. for two months they say they got training in weapons, explosives and hand-to-hand combat following his brother who had gone there in 2013 to join al qaeda in syria and

was killed in a battle last year. court documents say when he returned to his family's house in columbus he talked to others saying he wanted to target the military, police or anyone in uniform and wanted, to quote, kill three or four american soldiers execution style. his arrest is a first since isis began recruiting. >> this is the first case of an american traveling, you know, overseas to syria, training with terrorist groups there, then returning home to be arrested and indicted. >> reporter: he was arrested on state charges in february and had been under surveillance for months. tracing americans who have been to syria is an urgent priority for the fbi, as attorney general eric holder told us recently. >> we probably have hundreds under some kind of surveillance. >> reporter: authorities say tonight that mohamud's pro-jihadi postings on facebook helped attract the attention of investigators. his lawyer says tonight he will plead not guilty at a court appearance tomorrow, than he was caring for

his mother when he was arrested. lester? >> pete williams, thank you. now to that dramatic 911 call for help and the most unusual. for the first time we're hearing that airport worker trapped in the dark in the cargo hold of an alaska airlines plane in midair. the worker realizing where he is and pleading with a 911 operator trying to grasp exactly what it is that he is trying to tell her. our national correspondent miguel almaguer reports. >> alaska 448, prepare for takeoff. >> reporter: the alaska airlines flight was departing seattle bound for los angeles when the 911 call came in from the plane's cargo hold. >> 911. >> hello. i'm trapped in this plane. i called my job, but i'm in this plane. >> you're where? >> i'm inside the plane. i feel like it's up moving in the air. flight 448. can you please have somebody stop it? >> reporter: the caller, an employee at menzies aviation, who loads bags on to the plane, told authorities he took a nap. trapped with a flight on the move, dispatchers are confused. >> where are you in a

plane at? >> i'm inside a plane. alaska airlines plane flight 448. >> are you at the airport? >> i'm not in the airport. i feel like it's moved because i feel like -- >> reporter: the emergency call lasts 48 seconds, then suddenly drops off. yourself, or are you with somebody? >> reporter: with the plane climbing at 5,000 feet, passengers hear banging and a scream from below their feet. >> and he was like help, help. we're like what? >> reporter: airborne for 14 minutes, the trapped man was near the nose where it's pressurized and temperature controlled. the pilot made an emergency landing. the baggage employee able to walk off the plane. with the airlines still investigating, we were able to speak to that trapped man who called 911 over the phone this afternoon. he tells us he's in good health, back on the job and he says late tonight he's still feeling a bit tired.

lester? >> miguel almaguer, thank you. tens of millions of americans on the the alert for another multi-day of severe weather including tornadoes. alerts up already tonight. meteorologist dylan dryer is here with us. what areas concern you most right now? >> right now the southern plains where we're seeing most of our activity. we have a tornado watch in red here, but we also have several severe thunderstorm watches popping up in yellow. the biggest threat as we go through tonight besides an isolated tornado or two, will be for damaging wind gusts, up near 65 miles per hour. also some very large hail. tomorrow the threat is going to shift a little further into southern texas. you can't rule out a tornado, but we're still looking at our main threat as being of large hail and damaging wind gusts. over in the rockies, the concern has been the snow. take a look at denver where the snow plows are out once again. and on i-70 just west of denver, slippery roads were causing some accidents out that way. in the colorado rockies baseball

stadium, we were seeing that covered with snow because of the snowfall that we had in that area that we are looking at about 48 -- over the next 48 hours an additional 18 to 24 inches of snow. but the concern will be for the highest elevations. this is mainly for the ski resorts. we should see just an additional inch or so in denver. lester? >> all right, dylan, thank you. there's an alarming new warning tonight from the cdc about a dramatic jump in teens who use e-cigarettes. among high schoolers the number of students smoking or vaping e-cigarettes tripled in just one year. doctors warn that little is known about the potential health risks. here's nbc's tom costello. >> reporter: the splashy marketing is designed to lure a younger generation away from traditional cigarettes, but tonight the warning from the cdc is that e-cigarettes contain potentially dangerous chemicals and nicotine that carried their own health risks. >> we don't want to be playing a game of tobacco and nicotine whack-a-mole where we're addressing one type of tobacco product and allowing others to skyrocket. >> reporter: but that's what's happening. traditional cigarette

use has dropped to a record low, just 9% among teens, while e-cigarette use has tripled to more than 13% of all teens. 2.5 million people. another 1.5 million smoke hookah pipes. >> i enjoy it a lot more. i think it tastes a lot better. i think the smell is a lot better. >> reporter: ian king used to smoke a pack a day. now he carries bottles of e-cigarette flavors with him. so this is better, you think? >> yeah. i mean, you're not -- it's not like with cigarettes where you get tar in your lungs because it's a vape. it's like vapor. >> reporter: the fda hasn't decided whether to regulate e-cigarette sales to minors, but researchers worry that teens may be especially vulnerable. >> the biggest concern is nicotine. nicotine exposure to a developing brain, we don't know the impact of that. it hasn't been studied long enough. >> reporter: the cdc is concerned that the nicotine could lure kids into regular tobacco use. but the e-cigarette industry tells nbc

news the cdc's attack defies logic. e-cigarettes do not have any tar or any of the chemicals that are in tobacco. researchers admit they don't yet know all the risks and that is the danger. tom costello, nbc news, washington. turning overseas to iraq where a major city is in danger of falling to isis. thousands have reportedly fled ramadi which lies just 70 miles west of baghdad. the u.s.-led coalition is carrying out air strikes in three villages which isis militants overtook yesterday on the edge of ramadi. an update tonight on the search for missing malaysia airlines flight 370 still ongoing in the southern indian ocean. today malaysian officials said the search area will be expanded by another 23,000 square miles if the plane isn't found in the current search area by the end of may. malaysia, australia and china are leading the search to find the plane which vanished in march of last year. back in this country tonight, the nfl has reinstated the minnesota vikings adrian peterson. the star running back who missed most of last season while facing child abuse charges. the move clears the

way for peterson to return to the league pending he fulfill all the obligations of his plea deal with authorities. a true self-made success story played out on wall street today when etsy, the online marketplace where people sell unique and hand-made items, went public. the initial stock price was $16, but that quickly doubled at open. etsy which launched as a small company ten years ago, now has an estimated valuation of well over $3 billion. nbc's rehema ellis has our report. >> reporter: bill mowat and his wife started their company a-heirloom, making cheeseboards in the shape of states and selling them online four years ago. >> there's a bit of nostalgia, and it's a useful item. it becomes a conversation piece. >> reporter: and the personal touch is a moneymaker. up to $45,000 a month, double that during the holidays. >> it's important that we have a lot of control over the quality of things and what kind of materials

are being used. >> reporter: their small business is taking off with the help of etsy, the online marketplace founded ten years ago caters to artists selling vintage and hand-made arts and crafts. from leg warmers to glass-blown ornaments. now with a wide reach etsy has more than 1.4 million sellers, attracting nearly 20 million buyers with sales close to $2 billion last year. today the company that prides itself on having a majority of its sellers work from home made a big business move and went public. sellers are excited. >> they're hoping that it brings more eyeballs to their site and an even wider, more global reach than they had before. >> reporter: fashion designer rubin ruell is like 56% of etsy's sellers. he took his own money to start what is now a thriving business. >> in sales i'm pulling in over six figures a year.

and i would say that from 2013 to 2014 my sales did double. >> reporter: the challenge now is for the artists who turn etsy into a billion dollar company to hold on to that home-made appeal. rehema ellis, nbc news, new york. elsewhere on wall street today, a great day for etsy, but a down day for the market overall. all three major indexes finished slightly in the red. a lot more news still ahead on a busy thursday evening including the new warning tonight from doctors about the risks of snoring and sleep apnea. do they contribute to memory loss and possibly even dementia? also a warning that will warm your heart. a brave little boy and a loving father asking for help to wipe away his tears. you won't believe the response they got.

we have some news tonight that you need to hear if you snore or you're one of the long-suffering people who lives with someone who does. new evidence is out showing that snoring and sleep apnea have apparent links to something that scares us all -- memory loss. nbc's stephanie gosk has more. >> reporter: snoring can be maddening. often more for the people who have to listen to it than the people who actually do it. but new research suggests heavy snoring and the more serious condition, sleep apnea, could also have significant health consequences. both reduce oxygen levels to the brain and disrupt sleep. the study, published in the journal "neurology" reviewed

medical histories of more than 2,000 people between the ages of 59 and 90. heavy snorers and those with sleep apnea were diagnosed with mild cognitive impairment, a possible precursor to alzheimer's, about ten years before those who slept well. >> i don't think sleep apnea causes alzheimer's, but our hypothesis is that it might accelerate the process. >> reporter: it could be a contributing factor then? >> that's correct, yes. >> reporter: as many as 40% of all adults snore. men more than women. and those numbers only get higher as we get older. but there is treatment, including this breathing machine. >> that blowing air pressure basically acts as a stent to open up airway. >> reporter: is that uncomfortable at all? is it difficult to sleep with? >> it depends. some people find it a little bit difficult to get used to at first. >> reporter: patients who used one in the study delayed mental decline by a decade. researchers say the message to snorers is get help for both the person who sleeps next to you and your brain. stephanie gosk, nbc news, new york.

up next here tonight, cracking your knuckles. is it really bad for you like your mom used to say? tonight we finally have an answer. also the big "star wars" reveal. hans solo, chewy, our first look as some familiar faces return and some new ones appear.

one of the great mysteries of the human body may have been solved. scientists used an mri to see what happens when we crack our knuckles. they say the popping sound comes from a vacuum or a bubble forming in the joint fluid. and for anybody whose mom ever told them to stop, the study found no evidence that cracking your knuckles is harmful. scary moments for the country group lady antebellum whose tour bus caught on fire along the highway outside dallas this morning. singer hillary scott posted on social media that the bus blew a tire then the fire sparked forcing a fast evacuation. no one is hurt, though.

scott was on her way to dallas for this weekend's american country music awards. the release date feels so far, far away, but today the cast of the new "star wars" movie united on stage complete with androids. not among them harrison ford, who is said to be doing well after his plane crash last month. but fans did get a thrill to see him in the brand-new trailer. the first official look at ford playing han solo in over 30 years. when we come back, a father who asked for help cheering up his son. they never expected a response so big.

finally tonight, it started with a dad who wanted to help his young son feel better after surgery. neither could guess how many people it would touch. so many coming forward to let this little guy know that scars aren't merely reminders of trauma, instead they can be symbols of healing and bravery. here's harry smith. >> reporter: 7-year-old carter gentle was born with a

heart defect. he's had a dozen operations because of it. when he came home from the hospital after the last surgery, his scars made him cry. >> he was upset with the way he looked and how the scars made him feel. he was afraid that people would think he was ugly. >> reporter: so carter's dad mark posted a little message on facebook. >> i asked my friends to give him some likes and some comments just to make him feel better. >> reporter: then what happened? >> an hour later i looked at the post and it had a thousand likes and that thousand turned into, you know, 10,000. before we knew it, we were at 100,000, and as of right now we're sitting on about 1.4 million likes. >> reporter: likes and messages like these. scars are like a badge of honor! wear them proudly, my friend! you are a superhero! i think your scars are awesome just like you. oh, and the girls will like your scars when you're older.

i promise. and we all have scars. just some of us have ones that are more visible than others. you are perfect just the way you are. to help carter understand what was happening online, his dad set his phone to ping with every new post. >> he would just look at me with these big eyes. like, dad, i can't believe that's for me. you know, and it was just -- it was neat. it was really, really fun. >> reporter: today carter was playing outside like a kid without a care in the world. those scars maybe not such a big deal after all, especially with so many people on your side. >> awesome! >> reporter: harry smith, nbc news. >> i think carter's going to be hearing a lot of pings starting right about now. that's going to do it for us on this thursday night. i'm lester holt. for all of us at nbc news, thank you for watching, and good night.

>> announcer: nbc bay area news starts now. >> people wonder why he is causing the trouble that he is. >> right now at 6:00 advertising for a different archbishop. the papal plea coming from several high-profile san francisco catholics. good evening and thanks for joining us. i'm jessica aguirre. >> and i'm raj mathai. is the vatican paying attention to san francisco? it's a rare and high-profile move to oust the local archbishop. and it has bay area catholics taking sides. 100 local catholics have taken out this full-page ad in the

"chronicle," demanding action from pope francis, but will the vatican respond? nbc bay area's mark mathews is in san francisco. mark, the story and this ad generating a lot of buzz. >> it certainly is. you know the people behind the ad say that they tried for weeks to talk privately with the pope or his representatives, and it was only when those talks stalled that they decided to go public. archbishop salvatore cordileone has become a national voice in opposition to same-sex marriage traveling to the nation's capital to take part in demonstrations there. he maintains homosexual acts are inherently evil. he wants catholic school teachers to sign a morality clause supporting and abiding by those views, so opponents are taking the unprecedented step on calling on the pope to replace him. >> let me tell you that not only do the people who have signed this letter represent the broad spectrum of catholics in this diocese, they represent the very bedrock