How jumpy is it? Because of the way the graphics are designed, a bit of jumpiness is normal, but you should be able to hold a plane. It could be your iPad. Double tap the home button, then hold it down. Hit the little x button on all the apps, and it should speed it up. If that doesn't help, go into the Dogfight settings (in the app), and turn stuff off. Turn off clouds, use simple cockpit, etc.