50 busiest international airports by passenger travel according to Wikipedia, 2023. https://en.wikipedia.org/wiki/List_of_busiest_airports_by_passenger_traffic.
Codes given are IATA.
City answers are the main city the airport is intended to serve.
Start by naming any country that France borders. Then name any country that borders any of those countries. Then keep going until there are no more countries left to name.
Inconsistent.. NYC gets both New York airports, London only gets Heathrow. Having to type "London Gatwick" is a hard no as to nomination or a good rating.
It's funny to me how so many airport codes make sense based on either the city they service (BCN for Barcelona, SEA for Seattle) or the airport's name itself (LHR for London Heathrow, CDG for Charles de Gaulle) ... and then there's Canadian Airports - YYZ for Toronto, YYC for Calgary, YEG for Edmonton, etc.