Here is the full list of all 24 Air Conflicts: Secret Wars (EU) achievements worth 1,000 gamerscore.
100 players killed in multiplayer
5 multiplayer matches won with Red Air Force team
5 multiplayer matches won with Great War Team
50 multiplayer matches played
5 multiplayer matches won with Luftwaffe team
5 multiplayer matches won with RAF team
10 players in multiplayer killed without being shot down
Scored in top half in Deathmatch with at least 6 players
Scored first in Deathmatch with at least 6 players
5 players in multiplayer killed without being shot down
Extra long range Rocket Kill in Multiplayer
Long range Rocket Kill in Multiplayer
Chapter I Completed
Chapter V Completed
Chapter III Completed
Chapter VI Completed
Chapter II Completed
Chapter IV Completed
Chapter VII Completed
Every mission completed
All planes unlocked in single player campaign
100 aircraft shot down in Campaign Game
100 ground units destroyed in Campaign Game
Enemy aircraft shot down in single player with rocket at great range