Two aircraft that departed Boston 's Logan Airport on September 11 , 2001 , American Airlines Flight 11 and United Airlines Flight 175 , were hijacked by terrorists as part of the September 11 attacks . After the hijacked planes struck the World Trade Center , Boston Center air traffic controllers realized that both aircraft were Boeing 767s departing Logan Airport for Los Angeles . Delta 1989 fit the same profile as other hijacked flights : it had also departed Logan Airport for Los Angeles and was also a Boeing 767 . Boston Center staff notified the FAA about their suspicions at 9:19 AM Eastern Daylight Time when the FAA ’s New England regional office contacted the Herndon Command Center and asked Herndon to relay a request that Cleveland Center notify Delta 1989 to increase cockpit security . Herndon then ordered controllers to send a cockpit warning to Delta 1989 . Boston was tracking Delta 1989 and not receiving any radio contact from the aircraft . In fact , Delta 1989 was in Cleveland airspace and in contact with Cleveland Air Traffic Control Center
American Airlines Flight 11
American Airlines Flight 11
Delta Air Lines Flight 1989