To capture an airfield, the town is the key. If it's very close to the field, the town will have AirField guns that can reach it and add to the guns already in town. The way the 125th does it is to send in bombers to level hangers and town buildings, a couple heavy fighters to de-ck the town, couple fighters in case there are enemy aircraft in the area, and a goon to drop troops once town is flat.