The OAG Megahubs Index 2019 reveals the 50 most internationally connected airports in the world, the top 25 Megahubs for low-cost connections, the 25 most domestically connected airports in the U.S. and top 10s by region.

The index is generated by comparing the number of scheduled connections to and from international flights with the number of destinations served from the airport. The Megahubs Index harnesses the world’s most comprehensive schedules database to dynamically build connections through a dedicated analytics platform Connections Analyser and is further enhanced by OAG’s MCT Exception Table.





  • In 2019 London Heathrow Airport (LHR) continues to lead the world as the most internationally connected airport making it the Number 1 Megahub once again. OAG’s Megahubs Index calculates LHR’s score as 317, somewhat below where it was a year ago but still well ahead of its nearest rival. On the busiest day in 2019 the airport will have made possible a massive 65,294 potential scheduled international connections between arriving and departing flights within a six-hour window.
  • Frankfurt International Airport (FRA) rose to second place giving European airports both the number one and number two spots in the International Megahubs Index.
  • Munich (MUC) has made a significant move up the Megahubs Index, achieving a 22-point increase in the Connectivity Index and rising from 11th place last year to fifth place this year.
  • Singapore Airport (SIN) and Hong Kong Airport (HKG), ranked ninth and 10th, respectively. While SIN has dropped one place from 2018, HKG has risen up the rankings from 13th place as a result of a 1.5% increase in international connections achieved (within a six-hour window on the busiest day). In China, the highest ranked airport is Shanghai Pudong Airport (PVG) which was ranked 25th with a Connectivity Index of 163.




With airports and airlines themselves facilitating international connections between low-cost flights more and more, we have compiled the top 25 Megahubs for low-cost connections which include the same or different low-cost carriers.


  • Once again, Kuala Lumpur Airport (KUL) retains its position as the most internationally connected LCC Megahub in the world. With over 20,500 potential LCC connections in a 6 hour window, the airport has an LCC connectivity index of 150, considerably higher than the rest of the Top 25. Low-cost carrier AirAsia is the largest airline with 41% of all flights.
  • In fifth place, it the highest ranked non-Asian airport on the list and the highest placed airport in the Americas. SAN has seen above average growth in the last year and Southwest is the dominant carrier with 39% of seats. Incheon (ICN) moves up from seventh place to fourth this year with an increase in both destinations and potential connections.
  • Chicago Midway (MDW) climbs into the Top 25 in 18th place from 96th last year. Southwest dominates at MDW operating 89% of seats.
  • Incheon (ICN) moves up from seventh place to fourth this year with an increase in both destinations and potential connections. Manila (MNL) moves up into second place from fourth last year, whilst Singapore (SIN) remains in third place.





  • O’Hare remains most internationally connected airport in the US in 2019. Chicago O’Hare Airport (ORD) is ranked third, one of 15 North American airports listed among the Top 50 International Megahubs.
  • At ORD, United Airlines operates 46% of all flights but another four of the US International Megahubs – Atlanta Airport (ATL), Dallas/Ft. Worth Airport (DFW), Miami Airport (MIA) and Houston Airport (IAH) – operate   with the dominant airline having a 75% share, or more, of all scheduled flight operations.
  • Ranked second is Atlanta Airport (ATL) where passengers could make any one of a possible 63,466 domestic connections on the busiest day in 2019. Delta Air Lines’ dominance of flight operations at ATL continues with the airline operating 79% of all flights.
  • At the other end of the spectrum Los Angeles Airport (LAX) and Boston Airport (BOS) operate with the dominant airline having less than a third of flights, demonstrating that high connectivity does not depend on the presence of a major single committed carrier. At LAX the largest operator is American Airlines with 26% of domestic flights and at BOS JetBlue operates 29% of flights.
  • Overall, connectivity declined slightly with the Top 25 US Domestic Megahubs achieving an average Connectivity Index
    score of 123 compared to 128 in 2019. While individual airports moved up and down the ranking, the Top 25 airports remain the same Top 25 as last year.




OAG has calculated the total number of all possible connections between inbound and outbound flights within a six-hour window, where either the inbound, outbound, or both flights are international, at the largest 200 airports in the world (based on total scheduled seats in July 2019) and at the largest 200 international airports (based on total international scheduled seats in July 2019) on the busiest day for global aviation over the 12 months to July 2019.

For the purposes of this analysis, in addition to the in-built business rules within OAG Connections Analyser, the following customisable criteria were chosen for all operating flights:

  • Single international* connections only to/from the chosen airports.
  • Maximum circuity of 150.
  • Minimum Connection Time (MCT) varies by individual airport. OAG holds the MCT information for every commercial airport in operation.
  • Maximum connection window of six hours.

    *international connections include domestic to international, international to domestic and international to international connections

The US Domestic index uses the same methodology but has different criteria as follows:

  • Single domestic connections only to/from the chosen airports.
  • Maximum circuity of 120.
  • Maximum Connection Window of three hours.


Discover the 2023 Megahubs Index