Ok now I know naval units get interchangeable promotions like "normal crew' "buccaneers" and such to choose from to change and boost stats and such, and how Mechanos flying machines such as Thopters, Dirigibles and so forth gain these interchange promotions, I was thinking how about on top of those they get some of their own themed interchangeable promotion along with the naval ones. Heres some sample ones.
"Interceptor" -3 Attack, +2 Movement, 1.5x attack vs Flying, -50% defense (This means its attack strength against ground units is severely impaired, but it does a lot more bonus damage against flying so for instance....
Thopter (Without Interceptor)
Ground attack = 5
Air attack = 5
Thopter (With Interceptor)
Ground attack = 2
Air attack = 7.5
"Bomber" -3 Attack vs Flying, -2 Movement, -2 cargo, 1.8x attack vs ground, -50% defense
Thopter (Without Bomber)
Ground attack = 5
Air attack = 5
Thopter (With Bomber)
Ground attack = 9
Air attack = 2