One day at Area 51 a radar tech spots a single engine plane on final approach to the secret Air Force base. The plane touches down and is immediately surrounded by armed guards.
The plane is impounded and the pilot is whisked off for questioning.
The pilot claims that he had been flying from Las Vegas, gotten lost, and nearly run out of fuel, so he put his plane down at the first runway he saw.
After extensive background checks, it is proven that the pilot isn't a spy and he is set to be released the following morning.
Before he is allowed to leave, he is given the "You didn't see anything" talk, and is told that under absolutely no circumstances is he allowed to tell anyone where he was, or what he saw.
The Air Force fuels up the man's plane, gives him a proper heading to get back to Las Vegas, and sends him on his way.
Later that day, the man's plane is again spotted getting ready to land at Area 51.
This time there are two people in the plane.
When the plane touches down, it is immediately surrounded by guards again.
As soon as it comes to a stop, the man hops out and yells: "Do whatever you want to me, but SOMEBODY has to tell my wife where I was last night."