There's a thread for a "carrier airship" on this forum, and several on the old forum.
My opinion is that it's perhaps ok for AI, but for player controlled planes the physics if fixed-wing flight aren't very tolerant of lag and connection speed issues. The current four-person crew set-up is very strong and encourages team play, and most of the calls for planes are to introduce a single-player vehicle - that would change the competitive dynamic, and I don't think that would be for the better.