Princess Elizabeth Waves to Princess Margaret Leaving On Flight To Belfast to Launch New Liner "Edinburgh Castle" - Princess Elizabeth waving to Princess Margaret as the aircraft loft for Belfast, Northern Ireland, from London Airport. With the Princess is Sir John D'Albiac (Airport Manager *****). Princess Margaret left London Airport, Heathrbw, on the flight to Belfast,Northern Ireland, to launch the now liner Edinburgh Castle The Princess was soon off by her sister Princess Elizabeth, and flow in the Dakota aircraft normally used by Field Marshal Viscount Montgomery for special flights. October 14, 1947.