warren larson says he was being treated himself, given morphine, when he signed this airethods consent form for his daughter's medevac trip which in small print made him personally and fully responsnsle for the bill. >> they said, don't worry about it, it's just a standard form, just give us permission to ansport your daughter. >> reporter: nowhere on the standard form does it inform the patient or guardian of the expected cost. >> why don't you put the price here? >> i can get back with you on that. >> you're the vice president in charge of this. this is your standard form. why don't you put the price here so people know what they're signing on for? can ask. >> you don't know the answer? >> no, i don't. >> never been raised before? >> no, it has not. >> reporter:r:tate insurance regulators say they have been unable to rein in the prices or helicopter ambulance services because of a loophole in the federal law. al redner is the insurance commissioner in mamaland. >> when the federal government deregulated the airlines industry, these commercial helicopter companies were part of that. >

the bill from one company to transport the daughter of brenda and warren larson of kentucky was $47,000 for a 79-mile flight. and insurance only covered about a third of that. cripple us financially. >> reporter: jean medina got a $35,000 bill from the same company after her teenage gaugter, sophia, was air lifted 37 miles. >> it's just a crazy amount of money. >> reporter: the bills came from airmethods, the biggest for-profit air ambulance company, operating in 48 states, posting a profit last year of more than $100 million. company officials acknowledge airmethods charges far more than the actual cost of a flight, because they say they have to make up for underpayments by the poor and the elderly. >> look, if everybody paid their fair share, you know what the charge for this service would be? $12,000. >> reporter: but many insurance companies refuse to pay what they regard as the excessive cost, leaving the patients and their families on the hook. >> they said, don't worry about it, it's just a standard form, just give us permission to transport your daughter. >> reporter: but the st

. >> reporter: the bill to airlift warren and brenda larson came to $47,000 for a 79-mile trip and insurance covered about a third of that. and as is standard, the consent form he signed before the flight made no mention of the cost. why don't you put the price here so people know what they're signing on forsome >> it's a question i can't answer. >> reporter: and some wonder if helicopters are always necessary. jean's teenage daughter was airlifted after complications from a consellectomy. but it took almost an hour for the helicopter to arrive and lift off, and she was able to drive the 37 miles to another hospital in almost the same amount of time. >> i left a few minutes before they took off and arrived five minutes after they did. >> reporter: a ground ambulance would have cost $1,500. but the bill for the helicopter was $35,000. even after insurance and discounts, she still owes $17,000. >> it takes advantage of people when they are at their most vulnerable. >> learn more about the high dollar industry of medevac flight companies tonight on "nightline." >>> many people came together try