Hopefully they are looking for any non-transponder big jets flying around. And they couldn’t possibly make it across either ocean going at low alt because of fuel. It would take a serious operation to get it flying again at all. I’d imagine if it was taken the target wouldn’t be all that far away. I still think it was United 93’d most likely.
The Muzzies have to top themselves in relation to 9/11.
If they have computer techs working on the aircraft they could put in a legitimate transponder code, re-paint the aircraft, and do anything else to make it look legit. Then file a fictitious flight plan to the US and get into the system. No one would be the wiser among the many other aircraft flying on the NATRACK.