We _could_ do that, yes. BUT... The pilots navagate using GPS (do you really want to confuse a pilot unless you're ABSOLUTELY sure?) By the time you know for sure what's going on, it's likely too late. I've heard the 9/11 air traffic control recordings: the time between hijack confirmation and crash was seconds. And on a clear day with proper maps, jamming GPS won't do any good - the hijacker/pilot of the 4th 9/11 plane was following freeways.
[general rant] Stop this BS of clever "might work" cures - let the pilots carry guns so they can stop the b@$t@rds DRT.