Along the route, many people we spoke to said they heard coalition aircraft, sometimes drones, following the convoy.Notes
From the cab of his truck, Abu Fawzi watched as a coalition warplane flew overhead, dropping illumination flares, which lit up the convoy and the road ahead.
When the last of the convoy were about to cross, a US jet flew very low and deployed flares to light up the area. IS fighters [were very scared].”
 "Raqqa’s dirty secret." By Quentin Sommerville and Riam Dalati, BBC, 11/13/17.