Can a regular diamond frame bike be packed to fit as standard airline carry-on luggage?
You are correct that bike wheels are the dealbreaker—even if you could get the frame down to carry-on size, you won't get the wheels that small (although people have tried making collapsible bike wheels too).
There are full-sized bikes made with couplers, which can be taken apart and packed in a case with the same footprint as the wheels, and there are a few &quot;full-sized folders&quot; that look nearly identical to a conventional bike as well. But these will always be bigger than carry-on size. Attempting to bring one on board would require the indulgence of the cabin crew, and is not something you could count on.