Korean Airlines Flight 007 - while en route from Anchorage Alaska bound for Seoul, South Korea - strayed into prohibited Soviet airspace due to a navigational error prompting an intercept by soviet fighter aircraft.
The soviet aircraft promptly shot down the Korean Airlines 747, which resulted in the loss of 269 lives, including one sitting United States Congressman Lawrence McDonald.
This was one of the most tense moments of the cold war and resulted in President Ronald Reagan ordering the United States Military to make its GPS navigational systems available on the civilian markets.