Cryptic
Former Staff | Content Manager
I got Grim Reaper by using the old MW2 method. Got a two kills with one, earned another in the same match, then killed three with one with the second Pred I earned, and the challenge popped for me, so I don't see why they Airstrikes would be different.
If they, for some odd insane reason, don't work like the Predator one does, then I recommend Dome for the Air Strike, and maybe the new Central Park map or Dome or Village for the Stealth.
Less places to hide, greater the chance for a carpet bombing.