The airspace shutdown was over a dispute between the FAA and the U.S. military regarding plans to test a laser capable of shooting down drones used by Mexican drug cartels, sources tell ABC News. —–– Subscribe to ABC News on YouTube: https://abcnews.visitlink.me/59aJ1G Watch 24/7 coverage of breaking news and live events on ABC News Live: https://www.youtube.com/watch?v=gN0PZCe-kwQ&ab_channel=ABCNews Watch full episodes of World News Tonight with David Muir here: https://youtube.com/playlist?