At least three people are dead after a plane headed for the Boulder airport apparently collided with the towline of a small plane, causing a mid-air explosion. “The airplane came straight down,” said a witness of the larger aircraft. “It was on fire. When it was about 500 to 750 feet off the ground I saw the guys start to jump.” Debris from the crash fell in multiple locations and rescue teams are still working at the sites of the wreckage. “It’s still a very chaotic situation,” said a Boulder County official.