So as I was getting ready to upload this photo and write this blog, I realized one important thing. I didn't know the name of the things that were the reason I even took the picture in the first place. So...to Google.
Today's fun science fact: You know those white lines in the sky that follow jets? They're called contrails. They're formed when water vapor in the exhaust of the engine form ice crystals. This happens no matter what the temp is, which is why you see it in the summer too. Pretty cool huh?