President Trump signed an executive order Friday authorizing the Air Force to call up as many as 1,000 retired aviators to active duty. Trump’s order came as the Pentagon said it’s facing a large shortage of pilots as the administration prepares to ramp up the U.S. war in Afghanistan. Meanwhile, the Air Force says it will place nuclear-armed B-52 bombers on 24-hour ready alert for the first time since the Cold War ended in 1991.