A pair of runway incursions three weeks apart at Cleveland-Hopkins International Airport has investigators looking at the training process for new air traffic controllers. In the June 3 and June 26 incidents, the same controller in training was on position, though backed by different certified controllers supervising the trainee, CNN reported. In the first incident, a Southwest flight and a Continental Express flight were cleared to take off from the same runway at the same time. The crew of the Continental flight saw the other airplane and stopped, avoiding a collision by about 500 feet. In the second incident, an ExpressJet flight was cleared to taxi across the same runway that a CommutAir flight had been cleared to take off from. The ExpressJet plane stopped before crossing the runway when it saw the other plane. FAA officials said the responsibility for the incursions will lie with the two certified controllers who were watching the trainee when the incidents occurred. The air traffic controllers union said the trainee had completed less than a third of the required training hours on that position had received only 11 hours of training in June. The union attributed that low number of training hours to the large number of trainees, which has made it hard at some airports to pair certified controllers with trainees.