I can see a different class acting as captain, but it'd have to be someone aware of the battlefield in order to communicate with the other captains. An engineer has an awareness over the ship, a gunner has awareness of the enemy ship, a pilot should be in charge of being aware of every ships positions and movements, meaning they probably should be the one communicating, but, as I like to say with my weird build.. "Why not?" Whatever floats your airboat.