DALLAS — Two historic military aircraft collided and crashed Saturday during an air show in Dallas, exploding into a ball of flames and sending black smoke billowing into the sky. It was not clear how many people were on board. Emergency crews raced to the crash scene at the Dallas Executive Airport, about 10 miles from the city's downtown. News footage from the scene showed crumpled wreckage of the planes in a grassy area inside the airport perimeter. Dallas Fire-Rescue told The Dallas Morning News that there were no reported injuries among people on the ground. Anthony Montoya saw the two planes collide. I just stood there. I was in complete shock and disbelief," said Montoya, 27, who attended the air show with a friend. "Everybody around was gasping. Everybody was bursting into tears. Everybody was in shock." Officials would not say how many people were on board the planes, but Hank Coates, president of the company that put on the airshow, said one of the plan...