> Also, not sure why you wouldn’t just use Base64 encoding for which optimised versions already exist instead of rolling your own conversion to/from base 26 (or 52).

It's mentioned in the article, but base64 includes weird characters that might not be allowed in a name field, like `+=/`. I also wouldn't be surprised if the airline name field didn't allow numbers.

Reminds me a bit of this post: https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-...