Airplane Trails

O.K., I won't call them 'chemtrails' at this point, because I havent yet seen enough evidence for me to come to that conclusion. - But, I do know what I've observed with my own eyes. I often see criss crossed thick airplane trails that persist for hours (unlike contrails). This was not the case 10 years ago in my area.

Is there chemical testing evidence that shows that ground levels of certain chemical substances have risen ?

Is there actual evidence that airliner & other aircraft traffic has substantially increased during the last 10 years ? If so, what is the nature of that traffic ?

I remain open minded on this subject. Just want to see what evidence is out there.

Thanks