Here is the full list of all 9 Aces of the Luftwaffe trophies - there are 2 bronze, 6 silver and 1 gold.
Complete all Missions of Chapter 2
Complete all Missions of Chapter 1
Complete all Missions of Chapter 3
Complete all Missions of Chapter 4
Complete all Missions of Chapter 5
7777 confirmed Focke-Wulf kills
1337 confirmed Me262 kills
88 confirmed Ju88 kills
Rack up 25000 kills