This unofficial
5th Ed SRD actually covers a good amount of nautical related mechanics that I think would translate fairly well to airships. For the most part the mechanics are for non-standard sailing situations though: rough seas, perilous water, ship-to-ship combat situations etc. It assumes that the sailors are adept enough at sailing the ship under standard conditions, and won't need to check their abilities until those conditions change.
In the official Ghosts Of Saltmarsh book there was also coverage for ship combat, sea battles and traveling. I haven't looked at it in a long time though, and never thoroughly read the material so I can't really say if it is better or worse than the SRD mechanics.