1. Tunis, Tunisia (TUS)
to
Ottawa, Canada (YOW)
London-Heathrow, Paris-CDG, and Montreal.
2. Lublin, Poland (LUZ)
to
Gwangju, South Korea (KWJ)
Gwangju only flies to Jeju and Seoul-Gimpo, which themselves don't fly outside of East Asia, and Lublin only flies to Europe.
3. Pajala, Sweden (PJA)
to
Banjul, Gambia (BJL)
Pajara only flies to Lulea, but both Lulea and Banjul fly to several airports in Europe, they just happen to be different ones.
4. Sibiu, Romania (SBZ)
to
Kochi, India (COK)
Sibiu only has flights to Western Europe, and the farthest flights west from Kochi go to the Middle East.
5. Pskov, Russia (PKV)
to
Houghton, Michigan, USA (CMX)
Pskov-Sochi-Belgrade-Chicago-Houghton, most direct route I could find.
6. Bratislava, Slovakia (BTS)
to
Tottori, Japan (TTJ)
Tottori only flies to Tokyo-Haneda, but from there there are plenty of airports that fly to both Bratislava and Tokyo-Haneda.
7. Ube, Japan (UBJ)
to
Kazan, Russia (KZN)
Ube flies to Seoul-Incheon and Tokyo-Haneda, which fly to a good number of cities with Kazan flights, Shanghai, Dubai, etc.
8. Paramaribo, Suriname (PBM)
to
Bristol, UK (BRS)
Both airports fly to Amsterdam.
9. International Falls, Minnesota, USA (INT)
to
St Vincent, St Vincent and the Grenadines (SVD)
International Falls only flies to Minneapolis, but plenty of airports fly to both Minneapolis and St Vincent (Atlanta, Charlotte, Toronto, etc).
10. London, Canada (YXU)
to
Vancouver, Canada (YVR)
London flies to Calgary, Toronto, and 4 Caribbean destinations, but not Vancouver.
11. Regina, Canada (YQR)
to
Novokuznetsk, Russia (NOZ)
Novokuznetsk does have some flights to Southeast Asia, but they aren't to large enough airports to make a 2 layover route to Regina possible.
12. Kirovsk, Russia (KVK)
to
Sharjah, UAE (SHJ)
Both fly to Moscow-DME.
13. Ghardaïa, Algeria (GHA)
to
Aqaba, Jordan (AQJ)
Ghardaïa only flies to Algerian airports (and Medina and Jeddah), and Aqaba only flies to Istanbul, Cairo, Amman, and Cyprus.
14. Tampere, Finland (TMP)
to
Ittoqqortoormiit, Greenland (CNP)
Ittoqqortoormiit flies to Reykjavik and several smaller airports, and Reykjavik flies to Tampere's only 2 destinations, Riga and Málaga.
15. Praya, Lombok, Indonesia (LOP)
to
Stavropol, Russia (STW)
STW to Moscow SVO to Denpasar to LOP
16. Burlington, Vermont, USA (BTV)
to
Knock, Ireland (NOC)
Burlington flies to many large American cities, and Knock (which is the main airport for northwest Ireland) flies to many major European airports.
17. Santiago de los Caballeros, Dominican Republic (STI)
to
Pisa, Italy (PSA)
Both fly to Madrid.
18. Midland, Texas, USA (MAF)
to
Ottawa, Canada (YOW)
Midland has flights to Denver, Phoenix, Las Vegas, Austin, both major Dallas airports, and both major Houston airports, but none of them have a flight to Ottawa.
19. Belgrade, Serbia (BEG)
to
Erzurum, Turkey (ERZ)
Both have flights to Düsseldorf, and both have flights to several major Turkish cities.
20. Tahiti, French Polynesia, France (PPT)
to
Sal, Cape Verde (SID)
There was a flight during Covid that temporarily flew from Paris to Tahiti, which would make it a 1 layover route, but that flight no longer exists, so it requires two.
21. Las Piedras, Venezuela (LSP)
to
Sault Saint Marie, Canada (YAM)
Las Piedras has a route to Curacao, Sault Saint Marie has a route to Toronto, and Toronto and Curacao have routes to each other.
22. Caen, France (CFR)
to
Gwadar, Pakistan (GWD)
Caen only flies to southern France, Gwadar only flies to Karachi, and there are no direct southern France to Karachi flights.
23. Skagway, Alaska, USA (SGY)
to
Orlando-Sanford, Florida, USA (SFB)
The furthest Skagway flies is Juneau, the furthest Juneau flies is Seattle, and Orlando-Sanford doesn't have any flights west of SLC.
24. Wilmington, North Carolina, USA (ILM)
to
Turku, Finland (TKU)
Wilmington-Philadelphia-Copenhagen-Turku, among other routes.
25. Fargo, North Dakota, USA (FAR)
to
Osaka-Kansai, Japan (KIX)
Osaka has several flights to America (San Francisco, Los Angeles, Honolulu, and technically Guam), but none of those airports fly to Fargo, so it requires a second layover.
26. New York-JFK, New York, USA (JFK)
to
Ibaraki, Japan (IBR)
Ibaraki and JFK both fly to Shanghai (PVG) and Taipei (TPE).
27. Tbilisi, Georgia (TBS)
to
Salt Lake City, Utah, USA (SLC)
Both have flights to London-Heathrow, Paris-CDG, and Amsterdam.
28. Luleå, Sweden (LLA)
to
Cayman Brac, Cayman Islands, UK (CYB)
Cayman Brac-Miami-Stockholm-Luleå, this is the only route that works.
29. Namangan, Uzbekistan (NMA)
to
Medina, Saudi Arabia (MED)
No direct flights, the only airport in Uzbekistan with a direct flight to Medina is Tashkent, but there are several connections available, including Tashkent.
30. Rochester, Minnesota, USA (RST)
to
Sunshine Coast, Australia (MCY)
Sunshine Coast only has flights to 5 large cities in Australia and NZ (Sydney, Melbourne, Adelaide, Cairns, and Auckland), and Rochester only flies to Minneapolis and Chicago, neither of which have flights to Oceania.
31. Bermuda, UK (BDA)
to
Saint-Denis, Reunion, France (RUN)
Bermuda has a flight to London-Heathrow, and Saint-Denis has flights to Paris-CDG and Paris-Orly.
32. Belize City, Belize (TZA) (Not the main airport)
to
Bucaramanga, Colombia (BGA)
TZA is a smaller airport near Belize City, but it has a short flight to Belize's main airport, and Panama City and Miami both have flights to both Belize City and Bucaramanga.
33. El Alamein, Egypt (DBB)
to
Pula, Croatia (PUY)
El Alamein only has flights to Moscow-DME, Riyadh, Abu Dhabi, and Dubai, none of which have flights to Pula. Pula does have flights to most major European airports however.
34. Rotterdam, Netherlands (RTM)
to
Santa Cruz de la Sierra, Bolivia (VVI)
Barcelona has flights to both.
35. Hamilton, New Zealand (HLZ)
to
Brainerd, Minnesota, USA (BRD)
Brainerd only flies to Minneapolis, and no airports fly to both Hamilton and Minneapolis.
36. Reggio Calabria, Italy (REG)
to
Blantyre, Malawi (BLZ)
Reggio Calabria has flights to most major Western European airports, and Blantyre has flights to Addis Ababa and Johannesburg, both of which also have flights to most major Western European airports.
37. Saint Helena, UK (HLE)
to
Kumamoto, Japan (HLE)
Saint Helena only flies to Walvis Bay, Cape Town, and Johannesburg, and the farthest Kumamoto flies to is Taiwan, which isn't quite as far as Johannesburg flies, which is Shenzhen and Hong Kong.
38. Victoria Falls, Zimbabwe (VFA)
to
Norfolk, Virginia, USA (ORF)
Victoria Falls flies to all the large airports in southern and eastern Africa, and Norfolk flies to most large airports in the US, so there are a good amount of two layover routes.
39. Trieste, Italy (TRS)
to
Aarhus, Denmark (AAR)
Surprisingly, despite both having destinations all across Europe, only London-Stanstead flies to both.
40. San José del Cabo, Mexico (SJD)
to
Juba, South Sudan (JUD)
San José del Cabo has flights to almost every major US airport, and Frankfurt, and Juba has flights to most major airports in east Africa, and Istanbul, so there are a good number of two layover routes.
41. Annaba, Algeria (AAE)
to
St John's, Antigua and Barbuda (ANU)
It's not too far away from having a one layover route though, Annaba has several French destinations, and Antigua flies to Frankfurt, London-Heathrow, and London-Gatwick.
42. Aracaju, Brazil (AJU)
to
Rapid City, South Dakota, USA (RAP)
Aracaju is a domestic airport that flies to most major airports in Brazil, and Rapid City flies to seven major American airports, two of which have flights to Brazil, Chicago (São Paulo) and DFW (São Paulo and Rio de Janeiro).
43. Sveg, Sweden (EVG)
to
Livingstone, Zambia (LVI)
Sveg only flies to Mora (another small town in Central Sweden) and Stockholm, and the farthest into Africa that Stockholm flies to is Addis Ababa, and the farthest north that Livingstone flies to is Nairobi.
44. Redding, California, USA (RDD)
to
Thessaloniki, Greece (SKG)
Redding only flies to Seattle, SFO, LAX, and Denver, and Thessaloniki doesn't fly outside of Europe and the Middle East, but there are plenty of two layover routes available.
45. Havana, Cuba (HAV)
to
Asheville, North Carolina, USA (AVL)
Miami flies to both.
46. Terceira Island, Portugal (TER)
to
Pajala, Sweden (PJA)
Pajala flies to Luleå, and Zurich flies to both Luleå and Terceira.
47. Ciudad del Carmen, Mexico (CME)
to
Nagoya, Japan (NGO)
Ciudad del Carmen only flies to Minatitlán and Mexico City, and two airports fly to both Mexico City and Nagoya, Seoul-Incheon, and Tokyo-Narita. Mexico City also has a flight to Shenzhen, but Nagoya doesn't for some reason.
48. Brasília, Brazil (BSB)
to
Eastsound, Washington, USA (ESD)
Eastsound only flies to small airports in the Puget Sound area, and none of them fly to an airport with a flight to Brasília, even though Brasília has flights to Orlando and Miami, it isn't enough.
49. Dushanbe, Tajikistan (DYU)
to
Uberaba, Brazil (UBA)
Uberaba is a medium sized town in Minas Gerais, in central Brazil, with only two destinations, Belo Horizonte and São Paulo. However, Munich, Istanbul-IST, and Dubai all have flights to both São Paulo and Dushanbe.
50. El Paso, Texas, USA (ELP)
to
Dunhuang, China (DNH)
El Paso flies to most major airports in the US, and Dunhuang flies to most major Chinese airports, so there's a good number of two layover routes.
Then why doesn't it make one layover?