You might want to use something like this. I have a similiar device and it's enough to (re)start IL2 Pacific Fighters with:
When running the dogfight multiplayer game as described above the user would only have to use the "esc" key to enter the menu and then use the trackball to select "refly" and off you go.
When buying such a numeric keypad, make sure it has the "esc" key, not all of those devices have them...
If you don't want a keypad at all.... I'm not sure how to get out of the game/restart? Would have to investgate further...