I can't read past the paywall, but regarding the first photo (and the one I've seen the most), Kyle Hill makes a very thorough and compelling case for jet engin

I can't read past the paywall, but regarding the first photo (and the one I've seen the most), Kyle Hill makes a very thorough and compelling case for jet engine exhaust in IR, here: https://youtu.be/I_n1xpKBBcs?t=1074 https://youtu.be/I_n1xpKBBcs?t=1074