Lots of funny stuff about shooting it down misses the interesting question of how to get it up. At 65,000 the air is so thin that any lighter-than-air object has to be very extremely light. After the weight of the envelope and the helium (yes, helium weighs, too) there isn't much capacity left for the radar gear, solar cells and propulsion system. The wind up there keeps blowing the thing away, so it has to keep flying, and storing enough power to keep going at night is a huge challenge. DARPA and the Air Force have been looking for ideas on this, but I haven't seen any published solutions.
I tried to be helpful on counter-terrorism a couple of times. Sent a letter to Washington, full return address, phone, etc. Made another suggestion to the San Francisco Golden Gate Bridge Authority and got a visit from a special agent of the FBI. Sent him some more stuff by e-mail at his request. All since 9/11. FBI claims to have no record of any of it.
I used to fly those glass birds, and I have also watched the spoilers open up on a Boeing to reveal a complete jungle of hydraulic lines and valves. Maybe no problem flexing the wing itself, but what about all that junk inside it?