I guess there should be a Compressed Air class in every sub- and regular category. We'd almost catch up with the motorcycles.
I've seen some classed in other sanctioning bodies, 1-cyl., 2-cyl., 3-cyl. -- overhead, underhead, F-head, -- 2-stroke, 4-stroke, just stroke the official -- gas, alcohol, nitro, other -- seat higher than the cylinder head, green number plate, etc.
Everyone's a "World Record Holder" -- step right up with your checkbook.