I'm certain each flight has its own completely unique ID buried somewhere in a database. But, shorter codes can be spoken into a radio faster and with lower probability of misinterpretation - both critical features for air traffic control.
Those shorter codes will necessarily be reused, it's just a question of the time interval between re-uses of any particular code.
I faintly recall seeing two Southwest flights from ORD to BWI that had the same code a couple years ago, so I decided to look it up. And yes, it's a thing: Flight 1555 from ORD to BWI departs at 4PM today, and flight 1555 from ORD to BWI departs at 4:20PM tomorrow.
I'm curious, can anyone find a re-used code on a shorter time interval than that? It seems like 24 hours is perfectly reasonable, but how narrow can the window be? 12 hours? 6?
Those shorter codes will necessarily be reused, it's just a question of the time interval between re-uses of any particular code.
I faintly recall seeing two Southwest flights from ORD to BWI that had the same code a couple years ago, so I decided to look it up. And yes, it's a thing: Flight 1555 from ORD to BWI departs at 4PM today, and flight 1555 from ORD to BWI departs at 4:20PM tomorrow.
I'm curious, can anyone find a re-used code on a shorter time interval than that? It seems like 24 hours is perfectly reasonable, but how narrow can the window be? 12 hours? 6?