The reason Concorde stopped flying is because they were losing profit after a crash that killed several people on a Concorde Flight.
In the year 2003 Concorde was retired which was three years after the crash of Air France Flight 4590, in which all passengers and crew were killed.
After the crash in 2000 of the Concorde the passenger numbers fell as they were not getting as many people flying on the airline due to fears after the crash.
So they were losing money and had to stop flying the Concorde because they could not make enough money to keep it operating.
Although the Concorde flight had less passengers than some other airlines they could before the crash make a good profit because they could sustain high ticket prices.
Air France Concorde crashed minutes after taking off from Paris in July 2000, killing all 109 people on board and four on the ground.