You don't have to believe me. My only contention is that eyes can lie (particularly ground observation of objects at multiple thousands of feet); symptoms can easily be explained by other meteorological and environemental factors (we live in a polluted environment regardless of air travel). Air planes fly daily so its easy to point up and make conjecture that was the cause, but the fact is there is no scientific method involved in that kind of observation, so its perplexing (to me at least) that anyone would believe so deeply in such a fragile body of evidence.
A few decades ago? More than 3-5 decades ago there are pictures of this phenomena.