This is an example of false correlation in the human brain. You think you can see a pattern of planes affecting your radio but, in reality, it's just coincidence. You're obviously not winding up your radio enough or perhaps the rechargeable battery is knackered!

A good radio has circuitry to compensate for variable signal strength, boosting amplification when the signal falls, to maintain volume.

Low planes reflect VHF signals, and destructive interference between direct and reflected signal can cause the signal to fall and the circuit to boost, thereby draining the battery faster.

Add to that the regular spacing of planes in a landing pattern, being about the same interval as your battery life from one winding, and the presence of a plane is probably just using up the last flicker of power every time.