Here is the full list of all 45 Aces of the Luftwaffe achievements.
Defeat Commander Meiler
Complete all Missions of Chapter 5.
Bomb 2500 targets.
Rack up 25000 kills!
666 confirmed Ghost kills.
Bomb 40 AA gun nests! (Mission 3-2)
Defeat the Mad Scientist. (Mission 4-4)
Complete all Missions of Chapter 4.
Defeat Oberst Müller.
Complete all Missions of Chapter 3.
Bomb 30 AA gun nests! (Mission 2-3)
Evade all Mines. (Mission 5-3)
Bomb 3 Axis Airbases with the Allied bomber. (Mission 5-2)
Shoot down all 7 Ghost planes. (Mission 5-2)
Whatever those things are, kill them. (Mission 3-2)
Shoot down all three of the Super Planes. (Mission 2-3)
Bomb all the Axis panzers invading France. (Mission 2-2)
Bomb 500 targets.
7777 confirmed Focke-Wulf kills.
Need! Need! Need!
Rumor has it there's over 70 airborne. (Mission 3-3)
Defeat Major Kohler.
Complete all Missions of Chapter 2.
1337 confirmed Me262 kills.
Shoot down 15 Heinkel planes. (Mission 5-1)
Grab 5000 Medals.
Shoot down 10 Zeppelins. (Mission 4-2)
88 confirmed Ju88 kills.
Stay stealthy the entire mission. (Mission 4-1)
Shoot down 25 Bf110 planes. (Mission 3-1)
Kill a Fiat BR.20 bomber. (Mission 3-1)
Bomb 100 targets.
Defeat General Neumann.
Complete all Missions of Chapter 1.
Kill 300 Focke-Wulfs. (Mission 1-1)
Shoot down 5000 planes.
Bomb 6 Axis factories with the Allied bomber. (Mission 2-1)
Shoot down 50 jet planes. (Mission 1-3)
Down half a dozen heavy bombers. (Mission 1-3)
Collect 1000 Medals.
Collect 48 Power-Ups.
Kill 1000 foes!
Dance, dive bombers. Dance! (Mission 1-2)
Kill three Heinkel Bombers. (Mission 1-2)
Kill a dozen Messerschmitts! (Mission 1-1)