Large bike bags weigh around 7kg, and allow one to pack their best roadie, leaving perhaps 6kg spare for your bike shoes, nicks, jersey and helmet—unless you man-up and wear all that on the plane, as the dude pictured seems to be planning. But your woes would have only begun: taxis and some airlines balk at oversize items of luggage; your luggage shares the ride with your chain; your fellow conference delegates send word to your boss that you only went there to ride. Perhaps therefore one should be looking at the lightest possible folding bike, the 8.3kg Dahon Mu SL. Nice, but when folded it still doesn't fit into a suitcase! Okay, so we look at the 9.3kg minimal Brompton, which with a folding size of 585x545x270 would leave just enough room at the end of the biggest known suitcase in which to squish some silk shirts and moccasins, ready for a ripping time overseas dressed like Hugh Hefner, and what a winning look that would be with the ladies—I doubt it!
Regular road bikes equipped with Ritchey Break-Aways or S and S couplers, are a better solution, but still leave little room spare in one's suitcase. Even the 26" wheel versions are cumbersome, designed for long range riding abroad. For the global citizen simply wishing to explore cities gone to for business, even smaller wheels would make for the easiest possible pack, a flat bar would be fine, plus we might want single speed, again to reduce bulk and weight. Now before you say moosegoose, let me say: moosegoose! Yes, the stupidest contraption ever to disgrace a BMX track, just needs s and s couplers and the Dahon's ultra light little wheels, to be the basis of a bike that I would like to have with me while traveling.
Now before any of us say moosegoose again (and risk lightning strike from on high), I recommend the term used for the Tokyo hipster's mover of choice: mini-velo. Oh they've got a whole country going on over there in Japan, with no interest at all in what people think. And all I need is one of their single speed mini-velos, with s and s couplers, to never be bikeless again when I am abroad (actually, lower the standover, and I could be a broad, something I would love to try some time, though a long way from home). Back to the bike idea: if I made it out of Ti or stainless, I would not have to worry about paintwork scratching in transit. A belt-drive would solve the problem of business shirts being tattooed. And I could get this little baby to weight close to 5 kilos! If I went so far as to manufacture one with its own purpose built suitcase, then you know, you might just want one as well. $3000 for a 10kg suitcase, with plenty of room for wigs and high heels, oh, and a bike pops out on arrival! Anyone want one?
Postscript: on the advice of a reader, I have written to Bike Friday. Will keep you all posted. If this option works, I'll pick one up in the US. The prospect of collecting a bike directly from their Oregon headquarters, not far from Portland, is something for which I could sacrifice reason.