It feels like Airstrike should be a keyword ability (“Airstrike {2}”) rather than a keyword action. There’s just not much design space there, unless you let cards airstrike with other creatures.

@kyle dm  
Perfect! Flying warrior race is go!

@Phil Srobeighn  
Appropriately enough, the Pegasus faction these cards belong to is R/W and becomes full R/W/U in the third set.

Airstrike’s reminder text is imperfect, but I don’t think there’s room on a card for it to be perfect.
 
“During combat, after blockers are declared, if an attacking creature you control isn’t blocked, or if an a creature attacking you or a planeswalker you control isn’t blocked, you may cast this card for it’s Airstrike cost. If it’s your turn, it enters the battlefield tapped and attacking. If it is an opponent’s turn, it enters the battlefiled tapped and blocking target creature attacking you or a planeswalker you control.”
 
Yikes. You did the best you could with the space given. You would probably see about 5 creatures that are vanilla except for Airstrike and Flying so that all this text could fit in (three white pegasai, 2 red dragons? R/W is combat tricks, but W/U is flyers… but I can see some red pegasai…). A card like this would get no reminder text.
 
No matter how that works, the Airstrike should cost at least 2 more than the normal mana cost on non-Mythic Rares. The formatting would be Airstrike (Cost).