There are many ways to rank airlines: number of aircrafts, number of countries or destinations served, revenue or number of seats marketed.
This last criterion was used by OAG on the basis of the 2020 flight programs, and we learn some interesting things.
| Airline | Seats marketed in 2020 | |
| American Airlines | 265 043 191 | |
| Delta Air Lines | 243 372 169 | |
| Southwest Airlines | 210 911 808 | |
| United Airlines | 199 598 329 | |
| Ryanair | 151 419 618 | |
| China Southern | 141 365 190 | |
| China Eastern | 134 200 810 | |
| easyJet | 105 786 369 | |
| Air China | 93 627 708 | |
| Turkish Airlines | 93 355 469 |
Not surprisingly American Airlines and Delta dominate the ranking, while Southwest and United’s third and fourth places are simply the result of the specific characteristics of the U.S. market, where domestic flight frequencies are high and turnaround times are short, allowing the same seat to be sold many times in a day.
European low-cost airlines are also showing that they have to be reckoned with, with the presence of Ryanair and Easyjet.
The European airlines, except Turkish Airlines, are absent from the first ten places for exactly the same reasons that it is dominated by the Americans: their domestic or medium-haul market is far from being as developed simply because of distances and the quality of the rail infrastructure and, moreover, they face fierce competition from low-cost carriers in these markets.
As for Turkish, the airline that serves the most countries in the world, it is only in 10th place, to be compared with the surprising absence of Emirates. But an absence that is easily explained. Ranking airlines by marketed seats and not by fleet size or the number of seats “available” in the fleet favors airlines operating a dense medium-haul network where a seat can be marketed 2, 3, 4 or more times per day to the detriment of airlines with a large long-haul network that can only sell the same seat once per day. Turkish is thus helped by a medium-haul route that is almost non-existent for the Gulf airlines, despite the size of the Emirates fleet. A domestic network that also logically explains the good presence of Chinese airlines.
This ranking is far from being devoid of information, but it compensates for the real size of the airlines by the intensive use of medium-haul aircraft, and reflects the market structure rather than the performance of an airline, except for its ability to operate fast turnarounds.
Photo : American by CaseyMartin via Shutterstock

