This is a lightweight fiberglass case for bass trombones with a screw bell flare. The case is made in Brazil by Marcus Bonna, and fits a single or double valve horn with a bell up to 9.5" (24cm) diameter. The outer cover is easily removed and replaced if it ever needs repair, cleaning, or replacement. The inside features modular foam blocks to customize the fit to your instrument. The 12x16" (30x40cm) music pocket attaches with zippers and is easily removable. The pocket features loops to hold a trombone stand. There is a small storage compartment in the small end of the case, and a small pouch in the middle that may hold extra mouthpipes.
Though few of us have a trombone with a screw bell flare, those who do will find air travel to be very easy. This case would be welcome on most planes, and looks to be the size of a viola case. For rough travel we do recommend adding some extra padding inside so all parts are protected from each other. A few shirts or towels might do it. Though the shell is fiberglass, Mr. Bonna regards these cases as hand luggage. Your results when using baggage handling services may vary.
Shown in the photos is a Bach with a custom Kanstul CR rotor setup by John Sandhagen. It's the only screw bell bass trombone we could find for photos. As you can see, trombones with long open wrap valve loops may be too long for this case. We think axial rotor setups from various makers may fit fine. It is difficult to see, but the bell flare is in the case in the photos. It is under a small pyramid shaped on the left side of the case. The bell tail rests on top of it. We think the protection is is fine for local travel. Check your instrument against the dimensions above to get an idea of whether this may work for you.
Most airlines have a carry on bag size limit of about 50 linear inches. This dimension is calculated by measuring all the way around the short sides of the case, plus the long side. If you measure in imperial, a 10x10x30" case would be 10+10+10+10+30=70". This case is over the carry on limit, but the TSA has exceptions for moderate size musical instruments, up to the size of a guitar. Here are some guidelines as of 2014.