U can't get the AI to take off in the A-10 u say?? Can't see why not
When AI pilot is on the airfield, u only need to place the waypoint to where u want him to go....if u have waypoints on the runway this will slow him down....make sure his speed is set to full and also set his behaviour to 'Safe'....helps a lot too
[Edit]Make sure his skill level is set to full, also helps!!