It has to be the best level in the game, on veteran mode that is. Has anyone bet it? I tried it one night for 2 hours straight, not completing it once. Then I tried a different tactic, and it works every time! I'll give you my run-though (you've gotta be fast!):
1. Sprint immediately to toilet
2. Quickly switch to pistol
3. Knife man in toilet
4. Head into the cabin, keep walking straight
5. Toast the guy with the shotgun, then throw a flash-bang.
6. Pistol whip those fools.
7. Head up the small isle to your left, pick up P90, replace pistol
8. Two guys behind the double-entry, on left and right
9. Stick to you left, throw a flash bang, shoot people with P90 (then the cabin explodes)
10. Switch to MP5 and pity those fools coming down the staircase. Reload P90.
11. Head to the right-hand stairs, throw a flash at the roof and blind yourself.
12. Spray P90
13. Collect the 3 new flashbangs. Spam 2 through the text cabin.
14. Shoot, while walking forward
15. 1 more flash around the left corner, knife the guys
16. Keep running up to the FINAL terrorist, holding the hostage, and knife him in the kidney.
17. Tea bag him
18. Jump out of plane
19. ???
20. Profit