My Idea is for 3 bomber, fighter, and vehical factories to distributed around the outside of a countries HQ. These factorys would be similar to the underground ones Germany used and could only be penetrated by grand slam 22,000 bombs. These lancasters would not fly in formation and would be offerred at a perk cost. For each Factory destroyed would add 15 minutes of down time to the hangers and would only be down for 15 minutes, but could not be resupplied.