How about this, keep the "training" missions the same and add a new "Practice" area. Where you can fly any plane and practice bombing, landing, and just AI combat if you want. It needs options though, cause if I'm just trying to practice my bomb aiming i really don't want to deal with AI. I guess it would be a "free flight" mode with switches for AI aircraft, AI tanks, Zeppelin, Fixed targets (ground and air), and maybe even AI team mates.