Contrails, Condensation Vapour Trails

Head-on contrails
A contrail from an aeroplane flying towards the observer can appear to be generated by an object moving vertically. On November 8, 2010 in California, U.S., a contrail of this type gained wide media attention as a "mystery missile" that could not be explained by U.S. military and aviation authorities, and its explanation as a contrail took more than 24 hours to become accepted by U.S. media and military institutions.