Here's suggestions that I got for newer air force units
1). Messerschmitt BF-109
Excellent at maneuvering, excellent damage against Aircraft units, decent amount of damage against infantry and vehicles, limited damage against buildings, armored, and naval units
2). Junkers Ju88 A
Excellent damage against Army and Naval units, decent amount of damage against buildings
3). Spitfire Mk.II
Excellent against air units, decent amount of damage against infantry and vehicles, limited damage against buildings and naval