I use a Trico Iron Case bike box, a sturdy plastic reusable crate that fits a bike plus some accessories. It has a couple of wheels on one end and can be checked as luggage – for a price. United charges $100 each way in the US and $200 each way for an international trip.
the steps:
- shift to small chain ring and small cog
- remove pedals
- remove wheels
- remove skewers from wheels
- deflate tires
- remove co2 cartridges from the bike
- cover tubes with pipe insulation
- detach rear derailleur from hanger, wrap in heavy rag and strap to chainstay with velcro
- put dropout spacers in dropouts
- remove handlebars
- remove seat post – leave seat attached to post
- put frame and all parts in box except wheels – see photo
- put business card in the box
- put foam on top of frame
- put wheels on top of foam – see photo
- add instructional photos so TSA can reassemble box after inspection
- put foam on top of wheels
- put top of box on top of foam
- extend straps so that they can be attached and cinch them tight in increments
- tighten, tighten, tighten
- bon voyage
My experience is that the TSA always opens these boxes. They leave a calling card to let you know, although you can usually tell because they have to repack the box to close it.