 These were followed by Boulton Paul Balliol T.Mk.2s and Airspeed Oxford Mk.1s for advanced training of pilots and aircrew along with de Havilland Doves and de Havilland Herons for transport use, all provided by the British.By 1955 the RCyAF was operating two flying squadrons based at RAF Negombo.The first helicopter type to be added to the service was the Westland Dragonfly.