Last year, Brenda Freeman sent the link to NORAD Tracks Santa! - a Joint military effort (between Canada and America) to track and protect Santa on his flight delivering toys to all of the good little boys and girls.
Here's the details:
In 1955, a Colorado Springs based Sears placed an ad for local kids to "call Santa" on a special hotline that the department store had set up. No one seemed to notice that the hotline's number was misprinted. So instead of calling Sears on Christmas Eve, children all over the Colorado Springs area ended up calling Colonel Harry Shoup, director of operations at NORAD's predecessor CONAD, asking "where's Santa?"
(North American Aerospace Defense Command) is responsible for air and space
tracking, originally designed as a sophisticated detection system for inbound
Soviet ICBMs and nuclear-armed bombers.
Colonel Shoup realized what had happened, and played along. He asked his staff to check their radars to see if there was any indication of Santa moving on a south-ward vector from the North Pole. Thus, a tradition was born.
Every Christmas Eve, NORAD tracks Santa's journey around the world. Volunteers spend Christmas Eve at Cheyenne Mountain answering phone calls from kids all over the globe, while Air Force personnel from Canada and the United states track Santa using four high-tech systems: radar, satellites, Santa Cams and jet fighter aircraft.
According to the Track Santa website, Santa gets a fighter-jet escort upon entering North American airspace:
Canadian NORAD fighter pilots, flying the CF-18, take off out of Newfoundland to intercept and welcome Santa to North America. Then at numerous locations in Canada other CF-18 fighter pilots escort Santa, while in the United States American NORAD fighter pilots in either the F-15 or F-16 get the thrill of flying with Santa and the famous Reindeer Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen and Rudolph. About a dozen NORAD fighters in Canada and the United States are equipped with Santa Cams.