Another day, another round of cancellations at Heathrow Airport’s problem-plagued new Terminal 5. British Airways canceled 54 short-haul flights Monday and said more could be in store for Tuesday. According to an Associated Press report, nearly 300 flights have been scrapped and some 15,000 bags have been separated from their owners since the state-of-the-art terminal opened last Thursday. Airport operators have said the problems were triggered by glitches with the terminal’s high-tech baggage-handling system. BA, the only airline to fly from Terminal 5, said the terminal was working at 87% capacity Monday and service was returning to normal.