One way to mislead enemy missiles is to do a form of selective jamming. Instead of flooding all frequencies with noise, you make a signal that looks like an aircraft at a certain point in space, even though there's not really one there. So the missile heads towards this signal, and then another aircraft duplicates that signal and lures the missile further astray. A group of military aircraft can do this until the missile runs out of fuel. However, as this is not a new technology (as evidenced by the fact that I am posting this in public), there are ways to counter it: you just have a missile look for an origin of the signal instead of the signal itself; it passively listens for the signal instead of actively seeking it. Then it heads for the source.