In the final battle (over area 51 where the President is also one of the pilots), I found some slip-ups with the president's missiles.
First when he shoots the first missile, it hits the shield, the guys on area 51 saying the virus ain't working and that the pilots should disengage. Now, when the president activate his after-burner, look at the plane's missiles. There are 4 missiles, where there should be 3!
Another slip-up: The president fires 5 missiles instead of the normal 4. here's a count:
1) At the large alien ship (it still has shields)
2) At the large alien ship (with no shields)
3) At the large alien ship (when everyone are firing at the large ship
4) At one of the small alien ships (before shooting, he says "prepare to engage"
5) At the large alien ship (when the primary weapon opens)
Did the airplane got re-arm in mid-air or something? :)