|One particular airport is much more international than any other.|
The airports themselves are not a good source, as they typically count countries in imaginative ways. Hong Kong and Macau are typically counted separately (not as part of China) whereas Gibraltar suddenly counts as an own country. But there are only 198 countries in the world, and six of them do not have an airport.
|No airport is as fun as FUN, but Funafuti International|
Airport only serves one country outside Tuvalu.
Number two on the list is unlikely to catch up anytime soon. You can fly to 105 countries from Charles de Gaulle just north of Paris in France.
Two airports tie for number three, with 98 countries served by each. Frankfurt Airport in Germany and Dubai International Airport in UAE share the second spot while Amsterdam Schipol and London Heathrow trails badly with "only" 84 and 77 countries, respectively.
World's most international airports
1. Istanbul Ataturk IST 115 countries*
2. Paris Charles de Gaulle CDG 105 countries*
3. Dubai DXB 98 countries*
3. Frankfurt FRA 98 countries*
5. Amsterdam Airport Chipol AMS 83 countries*
6. London Heathrow LHR 77 countries*
|Barcelona BCN can't quite compete.|
The six airports combined will take you to 149 countries, or over 75 percent of the world's countries. But why no US or American airports on the list? The 35 countries in North and South America are simply too far away from the rest of the world, and you will in most cases have to transit at least once before you reach your destination. The same is the case with major airports in Northern Asia.
To be the most international airports do not necessarily make them the busiest. DXB is the world's 3rd busiest one with 78 million passengers annualy, LHR is 6th with 76 million while CDG comes in 9th with close to 66 million travellers. IST and FRA are 11th and 12th, according to Wikipedia. Hartsfield–Jackson Atlanta International Airport in the US tops that list by over 101 million passengers. These numbers do however include domestic passengers. If we take those away and only count international passengers, DXB is number one, followed by LHR, Hong Kong and CDG.
World's busiest airports, by international passengers
1. Dubai International Airport DXB 77,453,466
2. London Heathrow Airport LHR 69,816,491
3. Hong Kong International Airport HKG 68,139,897
4. Paris-Charles de Gaulle Airport CDG 60,369,798
5. Amsterdam Airport Schiphol AMS 58,245,545
7. Frankfurt Airport FRA 53,994,154
11. Istanbul Ataturk International Airport IST 42,302,859
Do note that I have not counted domestic flights from any of these airports. Doing so would add one more country to each of the four, but given that you are already in the country that didn't seem fair. The numbers are furthermore based on my own counts from the Wikipedia pages on each airport. There may be the odd inaccuracies.