The noise was somewhat reminiscent of the weeks following 9/11. It continued for about 15 minutes, paused for a few minutes, and then resumed for about 5 more minutes - at least over Montgomery County. Based on social media chatter, the jets were heard in the District and Northern Virginia, as well. Following the jet flyovers, commercial airliners were heard resuming landings at Reagan National Airport, in greater numbers than one usually hears along the Potomac after 11:00 PM.
A Google News search finds no news articles on the jet noise. In a tweet, Oriana Pawlyk, an air war reporter for Military.com, suggested the fighters may have been F-16s from Andrews Air Force Base.