These Are the World's Largest Airlines

Between the growth of airline travel and airline mergers, the industry's top players have become huge enterprises. But which airlines are the world's largest?

Let's see how the world's largest airlines stack up.

Revenue Passenger-Kilometers (RPKs)

One of the most widely-used measures of airline size — published each year by the International Air Transport Association (IATA) — is revenue passenger-kilometers (RPKs.) As the name suggests, this metric is the sum of the distances flown by each of the airline’s paying passengers over the course of the year.

Here are the airlines that flew the most passengers the farthest in 2018:

1. American Airlines (331 billion RPKs)

Thanks to its global network and its leading position in the massive US air travel market since its merger with US Airways, American Airlines carried the most paying passengers farther than any other airline in the world. However, Delta and United are close behind.

2. Delta Air Lines (330 billion RPKs)

After edging out United in 2015, Delta was again the second-largest airline in the world by passenger-kilometers in 2018 with 4.3% growth over 2017. Only half a billion RPKs behind American, Delta could well pass American in 2019, especially in light of American's quarrels with its mechanics union and the grounding of its 737 MAX aircraft for most of the year.

3. United Airlines (330 billion RPKs)

United Airlines once again was third among the world’s airlines by RPKs in 2018. Even if Delta passes American in 2019, it is neck and neck with United. Data for 2018 from the U.S. Bureau of Transportation Statistics showed United passing Delta in scheduled revenue passenger-miles, though the IATA data shows Delta still ahead of United by around half a billion RPKs. With United also affected by the 737 MAX grounding in 2019, Delta may come out on top.

4. Emirates (302 billion RPKs)

With its all-wide-body fleet and extensive worldwide network consisting largely of long-haul flights from its hub in Dubai, Emirates flew the fourth-most passenger-kilometers of any airline in the world in 2018 — and the most of any airline based outside of the United States.

5. Southwest Airlines (215 billion RPKs)

Southwest makes up for what it lacks in distance in pure volume. Despite operating only Boeing 737 aircraft on short-haul and medium-haul routes, Southwest still managed to rank behind only the US Big Three and Emirates in passenger-kilometers flown in 2018.

Southwest has been expanding its network with some exciting new routes, but its 2019 numbers will likely be diminished by the grounding of its 737 MAX fleet and its dispute with some of its mechanics earlier in the year, which have resulted in flight cancellations for much of the year.

6. China Southern (200 billion RPKs)

It’s no secret that China’s air travel market is growing rapidly. US citizens accounted for 18.6% of all airline passengers worldwide in 2017, but China ranked a close second at 16.3%. China Southern’s aggressive expansion brought it to the number six slot — and will likely take it higher in the years to come, even despite its recent departure from the SkyTeam alliance.

7. Ryanair (171 billion RPKs)

Ryanair isn’t known for having the most comfortable cabins. Neither is it known for the sobriety of its passengers. It is, however, known for ferrying a large number of passengers around Europe at low prices. Like Southwest, Ryanair operates only Boeing 737 aircraft on short-haul and medium-haul routes but makes up for the short distance of its flights in passenger volume.

8. China Eastern Airlines (166 billion RPKs)

The second-largest airline in the rapidly growing Chinese market, China Eastern passed Lufthansa for the first time in 2018, flying 166 billion RPKs. China Eastern will soon have even more capacity for growth, as they move in to the new Beijing Daxing International Airport later this year.

9. Air China (161 billion RPKs)

After bumping British Airways out of 10th place in 2017, China’s third-largest carrier has now also passed Lufthansa, moving into ninth place for 2018.

10. Lufthansa (159 billion RPKs)

The only European full-service airline to make the top 10, Lufthansa flew 159 billion RPKs in 2018.

Fleet

Another common measure of the size of an airline is the number of aircraft it operates. Airport Spotting created a list of the world's top 10 largest airline fleets as of the end of 2017. While many of the same carriers appear on this list as the revenue passenger-kilometers list, there are a couple of additional airlines that show up. One doesn't even carry passengers.

1. American Airlines (950 aircraft)
2. Delta Air Lines (850 aircraft)
3. United Airlines (745 aircraft)
4. Southwest Airlines (697 aircraft)
5. China Southern (545 aircraft)
6. China Eastern (486 aircraft)
7. Ryanair (413 aircraft)
8. Air China (392 aircraft)
9. FedEx Express (371 aircraft)
10. Turkish Airlines (329 aircraft)

American still holds the top spot, but China Southern may soon dethrone it. By mid-2019, China Southern's fleet had risen to 610 active aircraft, and it announced an ambitious plan last year to have a fleet of more than 1,000 aircraft by 2020.

FedEx's service may be ideal for boxes and other freight, but human passengers aren't likely to be on board all those planes.

Emirates took the number-four spot on revenue passenger-kilometers, but its fleet consists almost entirely of large widebody aircraft, so it accomplished that feat with only 268 aircraft, falling short of Turkish Airlines' 329.

It should be noted that this list contains only aircraft actually operated by each carrier, not regional aircraft operated by airlines under contract with the listed carriers.

Routes Served

Massive airlines like the US Big Three and the major Chinese airlines may move a lot of passengers, but their networks are based primarily on a hub-and-spoke model, limiting the number of direct routes between the other cities in their expansive networks.

Many low-cost carriers, however, arrange their route networks to take passengers from lots of different points to many other points. This pattern is reflected in anna.aero's list of the world's top ten airlines by number of routes for summer of 2019 schedules.

1. Ryanair (1,831 routes)
2. American Airlines (1,106 routes)
3. United Airlines (950 routes)
4. easyJet (945 routes)
5. Delta Air Lines (939 routes)
6. Southwest Airlines (754 routes)
7. China Southern Airlines (667 routes)
8. China Eastern Airlines (648 routes)
9. Wizz Air (615 routes)
10. Air China and TUI Airways (tie at 470 routes)

Although the US Big Three and the major Chinese carriers still had lots of routes, the point-to-point networks of low-cost carriers such as Ryanair, easyJet, Wizz Air and TUI give the latter group a major advantage in this metric.

(Photo via Getty Images)

For now, American, Delta, United and Southwest sit at or near the top in nearly every metric for measuring the world's largest airlines. However, with the rapid growth of air traffic in the Asia-Pacific region, it's likely that Chinese carriers and others in the region will continue to climb the ranks of the world's largest airlines.

This post has been updated with the latest figures as of 08/03/19.

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Image by John M Lund Photography Inc / Getty Images