Contrails, Condensation Vapour Trails

Condensation trails have been suspected of causing "regional-scale surface temperature" changes for some time. Researcher David J. Travis, an atmospheric scientist at the University of Wisconsin-Whitewater, has published and spoken on the measurable impacts of contrails on climate change in the science journal Nature and at the American Meteorological Society's 10th Annual conference in Portland, Oregon. The effect of the change in aircraft contrail formation on the three days after the 11th was observed in surface temperature change, measured across over 4,000 reporting stations in the continental United States. Travis' research documented an "anomalous increase in the average diurnal temperature change". The diurnal temperature range (DTR) is the difference in the day's highs and lows at any weather reporting station. Travis observed a 1.8 °C (3.24 °F) departure from the two adjacent three-day periods to the 11th–14th. This increase was the largest recorded in 30 years, more than "2 standard deviations away from the mean DTR".
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.