Aircraft scatter?

Martin G8OFA thinks that most random DX over 200km on VHF and UHF is due to aircraft scatter. I am unsure, but he points to the very high number of planes in the air. Certainly on the approach to the USAF airbases here and to Stansted, there will be lots of planes in the air nearly always.

I guess, without an SDR to help look at Doppler, my best bet would be to compare my vertical against my big-wheel. If many of the DX stations are coming though off aircraft, I assume the polarisation would be random. I seem to remember trying this some years ago and being surprised by the number of DX stations still being copied.

UPDATE 2046z: Maybe he is correct. I just connected the vertical omni V2000 and worked PD4HW (294km). Maybe I am consistently seeing aircraft reflections and there is always a very good chance of reflecting off aircraft. If I had a beam, I might expect better results then if I was beaming south towards the stack over Stansted Airport?