The Aérospatiale/BAC Concorde (/ˈkɒŋkɔːrd/) is a Franco-British supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC). Studies started in 1954, and France and the UK signed a treaty establishing the development project on 29 November 1962, as the programme cost was estimated at £70 million (£1.39 billion in 2021). Construction of the six prototypes began in February 1965, and the first flight took off from Toulouse on 2 March 1969.