this timbuk2 20-inch co-pilot roller luggage is an accepted size for a carry-on luggage on international flights.  i have used it as a carry-on flying on cathay pacific and united airlines.  i am not sure if the size is acceptable for domestic flights as i haven't tried fitting it in the "carry-on luggage check/verification" thingy in the airport.  the compartments serve well for its purpose and the luggage does seem to be sturdy.  the only downside is that this is quite a heavy luggage for carry-on.  it already weighs about 4kg and the allowed carry-on limit is 7kg so you are left with only 3kg of your stuff inside (that is if the airline would really weigh the carry-on's)