I thought it was stupid at first, until I began to notice something.
This semester, every day I went home early, feeling sick, dizzy, etc., I noticed that there were an awful lot of airplanes out, with those trails behind them. I don't just mean, one or two planes, but like 15 or 20 in the general AREA. I don't know what to think, it's probably coincidence, but it's definitely odd. Try and see for yourself, next time you're having a hard time focusing in school, or feel dizzy all day.