Across two successive Saturdays in July 1952, unidentified radar returns appeared over restricted airspace surrounding the U.S. Capitol. Air-defense jets were scrambled. Donald Keyhoe's NICAP began aggressive reporting in the aftermath. In a massive breach of secure airspace over the U.S. capital, ATC radar operators tracked numerous anomalous targets circling the Pentagon and White House over consecutive weekends. USAF interceptors were scrambled, but the objects routinely vanished upon visual approach, instantly reappearing on radar once the fighters returned to base.