MH370 is officially the flight with the most people to disappear, at 239 total people on board. Air France Flight 447 was a close second, though, at 228 missing people. Air France Flight 447, or AF447, disappeared on June 1, 2009. The flight was from Rio De Janeiro, Brazil, to Paris, France. People were finding similarities between the two disappearances. For example, both were commercial widebodies, and they were both transporting people internationally. What happened to AF447 was that the pitot tubes froze, which confused the pilots about the aircraft's airspeed and caused the Airbus A330 to stall and plunge into the ocean. People thought that the same thing could have happened to MH370.
This is AF447: