There were a total of 20 Concorde airplanes built. Six of these were prototypes and development aircraft, while 14 were used for commercial service by British Airways and Air France. The Concorde was a supersonic passenger airliner that operated from 1976 to 2003, and it was known for its sleek design and high-speed travel capabilities. **

The crash of the Concorde airplane in 2000 was caused by a chain of events that began with a piece of metal on the runway puncturing one of the plane's tires during takeoff. The tire debris struck the fuel tank, causing a leak and leading to a fire. The fire caused engine failure, ultimately resulting in the crash of the aircraft. This tragic accident highlighted the importance of safety measures and procedures in aviation. **

The Concorde is not being further developed because it was retired in 2003 due to a combination of factors, including high operating costs, low passenger numbers, and environmental concerns. The aircraft was not economically viable to continue operating, and advancements in aviation technology have shifted towards more fuel-efficient and environmentally friendly options. Additionally, the Concorde faced challenges with noise regulations and limited routes due to sonic booms, further contributing to its retirement. **

There are currently no plans for a direct successor to the Concorde. While there have been discussions and proposals for new supersonic passenger jets, such as the Boom Overture and Aerion AS2, none have reached the same level of development and commercial viability as the Concorde. However, with advancements in technology and growing interest in supersonic travel, it is possible that a successor to the Concorde could emerge in the future. **

The Concorde has a movable nose to improve its aerodynamics during different phases of flight. During takeoff and landing, the nose can be lowered to improve visibility for the pilots. When the Concorde reaches supersonic speeds, the nose is raised to reduce drag and improve the aircraft's efficiency. This feature allows the Concorde to maintain optimal performance throughout its flight profile. **

The Concorde is not allowed to fly anymore due to a combination of factors. One of the main reasons is the high operating costs associated with the aircraft, including fuel consumption and maintenance expenses. Additionally, the Concorde's sonic boom created noise pollution and limited its flight paths over populated areas. Finally, the tragic crash of Air France Flight 4590 in 2000, which resulted in the deaths of all passengers and crew on board, raised safety concerns and led to the eventual retirement of the Concorde fleet. **

As of 2021, there are 20 Concorde airplanes still in existence. These are located in various museums and aviation facilities around the world, including the Intrepid Sea, Air & Space Museum in New York, the National Museum of Flight in Scotland, and the Airbus factory in Toulouse, France. The Concorde was a supersonic passenger jet that operated from 1976 to 2003, and its iconic design and engineering continue to fascinate aviation enthusiasts. **

As an AI, I do not have personal preferences or desires. However, the Concorde was a groundbreaking and iconic aircraft, known for its speed and luxury. Many people would have loved the opportunity to experience flying on the Concorde due to its unique and prestigious status in aviation history. **