I do not know if it is current or not-taken before or after 9/11/01 and/or the new strict luggage policies. Just think that if it is still true, Brompton owners are not subject to the brutality of luggage handlers, or lost luggage of a valuable item.
The size stated: 2400 cu. in., 39.3 liters, L 22" x W 9.5" x H 13". is too small in the height. It needs to be about 20-22 inches to fit. 9/11 changed the way we fly. Things that once slipped on even in suitcases by are now closely scrutinize very closely. You could run the risk of not making your flight if your bike is not allowed-or fails to fit. I am not incline to bring any of my bikes or personal luggage-even the Brompton-with me if I can't carry on. That is why photos like this one offer some hope that I might be able to. I do not check in any parcels any longer. Too much chance of loss or damage.