In 1999 there was a professional golfer named Payne Stewart who died on a Learjet flight along with five others after it depressurized mid-flight. The plane continued flying on auto pilot and the FAA scrambled three separate fighter jet interceptions, involving five F-16s, the first one making visual contact with the Learjet approximately 20-30 minutes after the Learjet pilots became unresponsive. There was speculation at the time that the FAA was prepared to shoot the flight down if it was at risk of crashing in a populated area. The Pentagon later denied this, however, the Canadian government said this was their policy should the flight enter their airspace. [0]

[0]: https://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_cras...