I’ve been flying with mine in a Pelican 1535 Air, which is the maximum carryon size. The canister with head in fits perfectly lengthwise and my BOV, travel stand, handle, loop hoses, and some small odds and ends fit alongside. Counterlungs, wing, regs, and light fit in my backpack so I can carry on the entire unit and keep my checked bags under the weight limit. The TSA usually does a secondary screening but hasn’t been any trouble other than the time an agent unpacked everything to measure a box wrench I carry for the stand bolts.

They lose interest as soon as I tell them it’s diving equipment.