Establish signals with your subject pilot before taking off. Xavier is not cursing the Red Baron, he's asking the subject plane to hold it's relative position to the cameraship. With your headset you can relay some general requests to your pilot to pass along, but for smaller adjustments, hand signals work pretty well. Does it seem like Xavier could fall out of the airplane at any moment? Yes? It seemed like that to me, too. He has a lap belt on, but to be really safe, you should have a safety harness clipped to the plane somewhere.