The Jan. 29 collision over the Potomac River in Washington, DC — which preliminary reports have blamed on the military Black Hawk flying too high — was the deadliest US air disaster since 2001, and caused officials to change the flight path of helicopters near the airport.

Helicopters flying near Reagan National Airport caused flight diversions yesterday (Sunday) and Thursday. The first incident involved an Army Black Hawk helicopter taking a "scenic route around the Pentagon,