Ripsnort: Replicant's correct; combat ready aircraft were not kept in the hanger, ever. It was too big of a target and offered no portection. Serviceable aircraft were dispersed -- in three-sided revetments (earth or sandbagged berms as high as 10 feet) or under some kind of natural cover, such as trees. In Germany late in the war, a thick treeline adjacent to the take-off/landing field (paved runways were by no means the norm for dispersal bases) was a prerequisit for a fighter base. So concealment, physical protection, or both were used to make it harder to destroy your a/c on the ground. The hangers, if the base had any, were used as a place perform major servicing out of the weather.
The question then IS one of gameplay, as Replicant noted. Brand-W is planning on adding parked aircraft (as ground objects) to airfields in version 3.0. Destroying the parked a/c will affect aircraft availability at the base. Having them in revetments would make destroying them harder, since a direct hit would be needed to destroy an aircraft protected thus. I'd like to see bases use multiple revetments for fighters and perhaps the single hanger for bombers as spawn points. The fighter revetments would be harder to destroy, as a rule, then the bomber hangers. A larger field should have many revetments (10 or more), while small fields might have only 4. Food for thought.
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Sabre, a.k.a. Rojo
(S-2, The Buccaneers)