A comprehensive look at how the situation, which an anonymous U.S. official said appears to be coordinated and not the work of hobbyists, has unfolded so

Small, unmanned craft were seen flying over four bases in England, the U.S. Air Force in Europe said. The Pentagon said that there had not been “any significant mission impact.”

The Pentagon is “actively” watching for drones over U.S. Air Force locations in the United Kingdom, following a series of unexplained sightings over the past two weeks. The sightings, which took