Possible Clues:

• Santa Claus 'flight tracker'
• Org. that tracks Santa’s progress
• "WarGames" setting
• Org. featured in “WarGames”
• U.S.-Canada defense grp.
• U.S./Canada defense letters
• Defense org.
• Cheyenne Mtn. installation
• Air-defense org.
• U.S./Canada early warning syst.