It’s no surprise that the aliens/chemtrails crowd is convinced it was a missile.
In fact I would chalk this up as another reason to believe it was an airplane.
http://www.youtube.com/watch?v=_c6HsiixFS8
By “alien/chemtrails crowd” I’m assuming you mean the supposed ‘wacko people’ of which you have no faith in or belief that UFOs are real, but are ‘weather balloons’ or some other government cover-up phenomena. If that’s the case, I can tell you as a two-time CE-1 that they are existing crafts using exotic matter as propulsion. If you don’t know what a CE-1 one is or what exotic matter is by now, then you are hopelessly out of the loop and possibly light-years behind in your celestial and scientific knowledge and/or research. Move home, sheeple, if such is the case!!!