How about ride-a-longs?
Instead of "requesting" permission to jump in someone else plane, set it up with 3 options/check boxes.
"Ride along in a fighter"
"Ride a long in a bomber"
"Ride along in a vehicle"
Click on one of the options and the game drops you into a random players plane that is in the "action" area of the map.
The ride a long doesnt add any penalty so jumping in isnt going to hurt the players giving the ride along. If it is only allowable to 2 weeks.... err 4 weekers
it shouldnt be used to grief the player giving the ride a long.
This will show a new player more of the "action".
With the new videos the "radio" one should be repeated often and only a dot command in the radio bar can turn it off... insuring the new player knows how to use the radio to clear it.
The "free" set of planes in the MA is a big plus. Knowing that they are free indefinitely may take the pressure off and allow the new players to relax as they step into the deep end.
Maybe add a count of "AI" players in the "missions arena" on the login screen. "15 enemy AI, 5 friendly AI, in 5 missions going on right now!" As a scrolling message to attract attention to that arena.