I’ve been curious about this for a while. What happens to and/or who allocates the 2-letter airline codes. Have any two letter codes been re-allocated? I’m not good at civil aviation history but the recent demise of SR in leu of LX got me thinking. I’m sure that Pan-Am had their 2-letter code as well as TWA. And with so many low cost airlines having come and gone, 26 squared couldn’t be the limit, could it?