Hiring a Diplomat in the Tavern.
Crew are various NPC's within the game that provide different benefits when you hire them. They can be hired at any skyland's tavern from the moose bartender, and generally cost 50,000G. Different crafts have different crew capacities, and tier 0 and tier 1 planes cannot carry crew.
A sample "Crew Card".
Traders
Traders are the most common crew members, and help you, as their name suggests, with trading. They can reduce your buy and sell tax, and raise the bounty acquired from winning combats.
Mechanics
Mechanics repair your craft while in flight, as well as reducing the damage taken during combat.
Diplomats
Diplomats improve the quality of missions that will be offered by raising both influence and cash payouts, reduce the amount needed to bribe pirates and help smuggle cargo in the event that you lose a combat.
The most recent addition to the crew lineup, Navigators reduce flight time and can help you either steer clear of pirates while flying or steer into them if you're on the hunt.
Upkeep
Crew members will only do their jobs properly if they're kept happy. All crew have a salary of 500G per day. As long as they get paid, they'll stay happy and continue to help you.