The Rodriguez 6-pack design utilizes S&S couplings instead of 'folding' hinges and such. For this reason, the 6-pack is extremely light and very, very compact. It doesn't 'fold' in half, but rather comes apart very easily (the rear triangle does fold after the bike is apart), and is limited to the 20" wheel size for packing. A case or duffle bag that will hold the 20 wheels, will hold the whole bike.
The Rodriguez 6-pack will easily fit into a small aircraft luggage compartment and still leave room for plenty of other luggage.