I flew back to Germany in '98 and took my HT on the flight. Got a shipping box from my LBS and just checked it at the airport. Had to do some minor disassembly to get it in the box(removed wheelset and handlebars--left cables connected, tho). The box got a bit banged up in the cargo hold, but the bike was fine. Of course, I don't know how much stricter security's gotten. Haven't flown any more since '99/2000. It was well worth the hassle back then.
