Easily done in ground battles with BR around 1.5.
I would recommend going into battle with 3 tanks around BR 1.0, for example british, check which 1.0BR-1.6BR vehicles have air strikes that can be researched and play with them.
You will mostly play head on map where in the middle is shopping mall, simply try to shoot enemies and if you get air strike, use it on mutliple enemies (they might be grouped on main road), targeting mainly light tanks(icon: -), AAs(icon: _I_I_) and TDs(icon: /_) as they are most vulnerable.
You can get 3 air strike kills per match.
Tips: 1) the closer you are to the enemy, the more accurate the air strike (good to hide in that mall).
2) while trying to achieve this achievement, you can use british SARC MkIVa to complete South African Ace