Yes, that's how it may have been done on 9-11] --Terrorists could be prevented from carrying out September 11-style attacks by a device that would allow air traffic controllers to take control of aircraft and land them remotely. The device, known as 'Robolander', is among a number of pilot aides that the American government's Department of Homeland Security has asked Boeing to fit to new aircraft. Despite resistance to the technology from unions and airlines, the government may contribute up to £40 million towards a prototype "proof of concept" aircraft to be built by 2010. [Oh, there is little doubt the US government already 'has it' and possibly, has already 'used it.']
My personal take on the original authors commentary is BULLSHIT !!!
While the military has some stuff like this: http://www.navy.mil/homepages/vc6/bqm.ht
The technology exists here is the forum http://www.uavforum.com/
So you are free to decide with your own opinion. Not just what's given, by GLG.org author