jasonahn,
It’s all about the airline. If you are flying Korean Air, for example, look at their web site or call to find out exactly what is allowed. Each airline is different.
The problem is the airline may say one thing, but you may get told something else when you actually get to the airport. There are many restrictions on what you can bring into the airplane with you, especially on flights starting in the USA.
My guess would be that if your flight starts in Detroit, they will not let you carry on a 29" unicycle. Anything that does not fit under the seat is likely to not be allowed. Better to find a large duffel bag for it, and check it as a piece of luggage. For best results, let the air out of the tire, and surround the wheel with clothing or other padding, so airline people cannot tell there is a wheel in there.
Somrthing wrong in my writting above.
I mean of handcarry is not under the seat.
My question was “Possible to send luggage?”
Butl, I think it is possible to be with me.
I think that I will disassembly all of parts and repacking it for more compact size.