Mexicana de Aviación Flight 801, a Boeing 727-100 passenger plane, crashes during a landing attempt in Mexico City, killing 27 of the 118 occupants.

Mexicana de Aviación Flight 801 was a scheduled international flight from Chicago-O'Hare International Airport in Illinois bound for Mexico City International Airport, Mexico City. On September 21, 1969, the Boeing 727-100 crashed during its final approach to Mexico City International Airport. The aircraft broke apart upon impact, killing 27 of the 118 occupants on board. The cause of the crash was never determined.

September 21 is the 264th day of the year in the Gregorian calendar; 101 days remain until the end of the year.