I think favour is a airship's defensive stat in how it deals with adverse weather and is best used on exploratory airships.On retreival airships it should be minimized to the lowest amount required. Don't know yet and will do more testing, I'll post some logs in the coming weeks.

Anyway I dunno how useful my information will be but inorder to max out survallience on a airship you can use my fc's airship build.

Tatanora forecastle
Enterprise Hull
Odyssey Bladders
Bronco Aftcastle

All told your stats will end up this.

140 Surveillance
56 Retrieval
126 Speed
82 range
132 Favour

Primary purpose is for short quick double sector exploration. Obviously this ship isn't going to bring back things in great numbers but there should be no sector it cannot discover in theory.