Around 03:13 UTC on 21 June (22:13 local time) a flight of US Air Force KC-135 Stratotanker aerial refueling aircraft departed Altus Air Force Base in Oklahoma. Operating in two flights of four aircraft, the Stratotankers headed northeast toward Missouri. Those aircraft quickly climbed to the top of Flightradar24’s most tracked flights list—not because thousands of people find aerial refueling aircraft over the central US fascinating, but for the inference of their purpose.