The downside to country codes is that countries can change (split, merge, or rename) even when the airports within them haven't.
And the idea that the system would fall apart into one where each country manages their own codes doesn't make sense. As stated in the video, the 3 letter codes come from the IATA. Their members are airlines, not countries. They can assign codes in whatever way works for them to communicate with each other where passengers and their bags need to end up.
And the idea that the system would fall apart into one where each country manages their own codes doesn't make sense. As stated in the video, the 3 letter codes come from the IATA. Their members are airlines, not countries. They can assign codes in whatever way works for them to communicate with each other where passengers and their bags need to end up.