Found this on Wikipedia in regards to the Munich '72 Olympics:
“On 11 September a small plane was stolen in Stuttgart and authorities received information that Arab terrorists were planning to drop a bomb on the final ceremonies. IOC officials and Chancellor Willy Brandt, who were attending the ceremonies, were informed. Defense minister Georg Leber had two fighter planes follow the stolen plane, with the intent of shooting it down should it approach Munich. Radar contact to the plane was lost. A short while later, radar contact to an unknown plane was established, but it turned out to be a civilian passenger aircraft. The stolen plane was never found.”
I just found it interesting that a bunch of radical Arabs terrorists hijacked a plane on September 11th. Striking similarities.