John wrote:
Almost any aircraft can be rolled whether barrel or aileron.

Well, any fixed-wing aircraft (including, I would guess, most gliders). I
suspect you're going to have a hard time rolling an airship or a hot air
baloon, however.

One of the coolest things I've seen is a helicopter do a roll (at Farnboro
airshow). That was amazing. I had always though helicopters were not
capable of doing anything like that.