Is the ICAO24 a unique identifier for an aircraft (there are aproximately 380 000 distinct ones and google says there are so far 38 000 aircrafts in the world so i feel like no),
If no can you help me know which field can help me identify an aircraft ?
It is a unique identifier for an aircraft, well more accureately for a transponder. There are definitely more than 38000 aircraft in the world - as you can see from the flight table. It's only changed when the aircraft is re-registered (let's ignore miltiary aircraft and the FAA's ill-fated PIA programme).