A United Airlines flight to Washington, DC, was forced to make an emergency landing after the Boeing plane abruptly plunged in midair, hurting nearly 40 people onboard, including six hospitalized with serious injuries, according to officials and video of the chaos. United Airlines Flight 613 turned back to Nigeria on Jan. 24 when the aircraft suddenly plunged 93 minutes into the trip to Dulles International Airport, according to Flightradar24 data.