I just flew to Arizona and back with my bike on American Airlines. First time I've ever done that. I used an old Colorado Cyclist bike box. Same size as a regular box but it lays flat with a separate lid. Like a hat box I suppose. Anyway it was really easy to pack. Seatpost out, handlebars out, wheels off and that's it. I had to repack it a few times to get under the 50# airplane limit and it was pretty smooth. I've been pretty lazy and still haven't gotten the bike back together. Big foam pad on the outsides and one in the middle. In this case I used a sleeping bag and pillow in the middle. I just put extra foam padding or bubble wrap at places where I thought there might be metal on metal contact. If you come across this style box, grab it.
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N = '96 Colnago C40, '04 Wilier Alpe D'Huez, '10 Colnago EPS, '85 Merckx Pro, '89 Merckx Century, '86 Tommasini Professional, '04 Teschner Aero FX Pro, '05 Alan Carbon Cross, '86 De Rosa Professional, '82 Colnago Super, '95 Gios Compact Pro, '95 Carrera Zeus, '84 Basso Gap, ‘89 Cinelli Supercorsa, ‘83 Bianchi Specialissima, ‘VO Randonneur, Ritchey Breakaway Steel, '84 Paletti Super Prestige, Heron Randonneur