without range icon , you dont hit anything flying around, with a tank.
I've scored one helicopter "kill" using bt-41 laser system, during a drill, using target computer at closer range with a 90mm tank gun.
we shot targetpractising with mg's against flying targets towed by c47's flying straight close nearby.
There are many reasons you do not hit planes with main gun in tanks IRL.
Crew workload, if you do not have a shot ready in the barrel , not even think about it.
Gunner view arc is VERY limited, also he will not be supplied with range for adjustment to range at something flying ( icons are rare IRL

)
If you finally track the flying target with main gun , still not knowing range , and you see through magnification , I say chances are close to 0.
Gun traversals and preciseness using electrics tricky ww2.
If tank is not exactly level in all axis difficulty are increased even higher.