Complex sentence: A major upgrade program for the A330 could also cause problems for Airbus: the re-engined A330 would be launched into a twin-aisle market already crowded by the Boeing 787,777X, and Airbus A350, and could take sales from other Airbus aircraft.
Split into simpler sentences: A major upgrade program for the A330 could also cause problems for Airbus. The re-engined A330 would be launched into a twin-aisle market already crowded by the Boeing 787,777X, and Airbus A350, and could take sales from other Airbus aircraft.