joined by narc new and aaron levy. i'm going to apologize, and i think you saw that setup coming that i'm going to apologize. it'll never work, it's been tried before, and nobody wants it. what's your reaction? >> well, it has been tried before. the thing about supersonic travel is it's not new, it's existed for 50 years. the problem was the technology hasn't existed to make et affordable for practical travel. so concord, roundtrip ticket new york to london would set you back $20,000. that's a bucket list kind of thing. that's not transportation. but fast forward 50 years, we have the technology to doitd in a way more affordable way. >> what technology? the materials? >> it comes down to three things -- aerodynamics, materials, and propulsion. aerodynamics, build in simulation a much more aerodynamic design than you can develop in a wind tunnel. materials, light weight, stronger rs that can take higher temperatures, better for the stress of supersonic flight. and engine technology. concord flew an afterburner, which it