The aviation industry is heavily dominated by two major players: Airbus and Boeing. While the latter's dominance has largely lagged behind the former, Boeing aircraft continue to comprise a large majority of airline fleets.

Today, we will analyze the five airlines with the largest Boeing fleets. This list will change over the years as some carriers have hundreds of Boeing jets on order.

American Airlines

It should be no surprise that most airlines on this list are based in the United States. Currently, American Airlines has 491 Boeing aircraft in its fleet consisting of the following breakdown:

• 303 Boeing 737-800s
• 62 Boeing 737 MAX 8s
• 47 Boeing 777-200ERs
• 20 Boeing 777-300ERs
• 37 Boeing 787-8s
• 22 Boeing 787-9s

The carrier is the largest operator of the 787-8 and has 30 further orders for the larger 787-9. Furthermore, the airline has 38 more MAX 8s and 115 737 MAX 10s on order.

Delta Air Lines

The next airline on the list is competitor Delta Air Lines with 513 Boeing jets in its fleet. Delta has steadily decreased the amount of Boeing planes in its fleet over the years, most notably retiring its entirely 777-200ER and 777-200LR fleet during the pandemic.

In recent history, Delta also flew 747-400s and 737-700s that were retired in 2019 and 2020 respectively. Currently, Delta's Boeing fleet consists of the following aircraft:

• 88 Boeing 717-200s
• 77 Boeing 737-800s
• 163 Boeing 737-900ERs
• 105 Boeing 757-200s
• 16 Boeing 757-300s
• 43 Boeing 767-300ERs
• 21 Boeing 767-400ERs

Delta's Boeing order book has dried up over the years, as the airline shifts its future fleet plans to revolve mostly around Airbus planes. Currently, the airline has 100 Boeing 737 MAX 10s on order.

Ryanair

European low-cost giant Ryanair is the only non-American carrier to make the list. With 571 Boeing jets in its fleet, the Boeing 737 is one of the driving factors behind Ryanair's massive growth.

Ryanair has remained largely loyal to the 737 program over the years. While the airline did not start out with 737s, the carrier has flown the 737-200, 737-300, and 737-400 in the past.

Currently, Ryanair's Boeing fleet consists of all 737s with the following breakdown:

• 1 Boeing 737-700 (operated for Polish tour companies on charter flights)
• 410 Boeing 737-800s (largest operator)
• 160 Boeing 737 MAX 8-200 (largest operator)

The 737 MAX 8-200 is a higher-density variant of the MAX 8. Ryanair is the only airline operating this type. Its 737-800 and MAX 8-200 fleets are spread out across multiple carriers.

Aside from the main Ryanair which operates most of these aircraft, the airline also owns subsidiaries Malta Air, Polish subsidiary BUZZ, and Ryanair UK. 

Ryanair remains committed to the 737 for its future, having orders for 50 MAX 8-200s and 150 MAX 10s.

United Airlines

Shifting back to the United States, United Airlines is next on the list with a current Boeing lineup of 788 planes. United has the most variety of any carrier when it comes to Boeing aircraft:

• 40 Boeing 737-700s
• 141 Boeing 737-800s
• 12 Boeing 737-900s (non-ER)
• 136 Boeing 737-900ERs
• 98 Boeing 737 MAX 8s
• 80 Boeing 737 MAX 9s
• 40 Boeing 757-200s
• 21 Boeing 757-300s
• 37 Boeing 767-300ERs
• 16 Boeing 767-400ERs
• 19 Boeing 777-200s (non-ER)
• 55 Boeing 777-200ERs
• 22 Boeing 777-300ERs
• 12 Boeing 787-8s
• 38 Boeing 787-9s
• 21 Boeing 787-10s

United is the largest operator of the 737 MAX 9 and 757-300. It was also the launch customer of the Boeing 777 program, continuing to fly the world's oldest active 777 examples. These include the second ever built (N774UA) and the first 777 to enter revenue service (N777UA).

United remains committed to Boeing jets to power its future. Despite having sizable Airbus orders, United has 25 MAX 8s, 143 MAX 9s, 167 MAX 10s, and 150 787s on order. United has expressed concerns regarding the MAX 10 and it's unclear if the airline will move forward with that order.

Southwest Airlines

In first place is American low-cost innovator Southwest Airlines with 816 Boeing jets in its fleet. Southwest is the only airline on this list with an all-Boeing fleet (Ryanair technically has 27 A320s flying under Lauda).

Southwest has remained an all-737 airline for much of its history. The carrier briefly leased seven Boeing 727-200s that it flew from 1978 to 1985. Aside from that, the airline has operated the 737-200, 737-300, and 737-500 in the past.

Southwest's fleet consists of the following aircraft:

• 375 Boeing 737-700s (largest operator)
• 205 Boeing 737-800s
• 236 Boeing 737 MAX 8s

The airline has 307 Boeing 737 MAX 7s on order and 169 737 MAX 8s on order.