There's been a lot of posts on this recently so I would like to clarify this.
SOoooooooo much in CoW is implied. There are refuel ships in fleets, there are escorts with transports, there are engineers with tanks, just it is all implied.
Also, when patrolling only 50% of damage is dealt, meaning that only 50% of aircraft are in the sky. For attacks, the aircraft do land and refuel.