United Airlines Leads with World’s Largest Mainline Fleet in 2025

United Airlines has claimed the title of the world’s largest mainline fleet in 2025, boasting a remarkable total of 1,056 aircraft. This fleet, which does not include aircraft operated by alliance partners or regional subsidiaries, includes almost 250,000 seats available for passengers. This article explores the composition of United’s extensive fleet and highlights the competitive positions of American Airlines and Delta Air Lines, which follow closely behind.

United Airlines: A Massive Fleet Overview

United Airlines stands out as the dominant player in the airline industry with a diverse array of aircraft. Its most prevalent widebody option is the Boeing 777-200ER, with 55 units in service. However, the airline operates an extensive lineup of narrowbody jets, showcasing four variants of the Boeing 737, each with over 100 examples, including the 737-800 and 737-900ER.

The accompanying table provides an overview of the top five widebody and narrowbody aircraft in United Airlines’ fleet:

In addition to its current fleet, United Airlines maintains a significant array of retired aircraft, including older variants of the Boeing 737. The carrier has ordered 167 Boeing 737 MAX 10s to ensure its fleet remains competitive. Furthermore, a notable reduction in widebody jets includes the retirement of 44 Boeing 747-400s, reflecting a shift in operational strategy.

Delta Air Lines and American Airlines Close Behind

Delta Air Lines ranks second with a mainline fleet comprising 1,010 aircraft. Similar to United, Delta’s fleet features an emphasis on narrowbody jets, with 158 Boeing 737-900ERs and a substantial number of Airbus A321s. Delta’s widebody fleet remains modest, primarily consisting of smaller jets like the A330-900 and Boeing 767-300ER.

A snapshot of Delta’s fleet is as follows:

Delta Air Lines anticipates future growth with 267 firm commitments on its order sheet, including 100 Boeing 737 MAX 10s and investments in next-generation widebody aircraft.

American Airlines rounds out the top three with a mainline fleet of 1,001 aircraft. The airline operates a fleet entirely composed of Boeing widebody jets, including 67 Boeing 777s and various models of the Boeing 787 Dreamliner.

The distribution of American Airlines’ fleet is illustrated below:

American Airlines is also poised for future expansion, with 300 commitments that include 115 Boeing 737 MAX 10s and a focus on the next generation of widebody aircraft.

Looking Ahead: United Airlines’ Future Plans

United Airlines’ extensive order sheet positions it to maintain its lead in the airline industry. The carrier has 666 jets currently awaiting delivery, which reflects an aging fleet with an average age of 16.9 years. This indicates a strategy to phase out older aircraft as new deliveries come in.

The breakdown of United’s orders reveals a heavy commitment to the Boeing 737 MAX 10, although certification delays have led the carrier to rely on the Boeing 737 MAX 9 for immediate capacity needs. Andrew Nocella, Chief Commercial Officer of United Airlines, stated, “In supply chain terms, we want to make sure we get our aircraft, so we’ve committed to the MAX 9. Until we know the MAX 10 is going to be delivered, we don’t want to have an aircraft that doesn’t arrive.”

United Airlines has opted not to add the Boeing 777X to its fleet, as its operational model does not align with the high-capacity jets. This decision aligns with the airline’s multi-hub approach, which allows for efficient long-haul operations without the need for new aircraft.

As United Airlines prepares for a busy travel year, it has scheduled 1.6 million flights in 2024, serving 944 routes. Its busiest domestic route connects Chicago to LaGuardia, with an average of 14 flights per day.

Moreover, the airline maintains a robust international presence, flying to 122 destinations outside of the United States. Toronto Pearson International Airport ranks as the busiest international destination, with 697 flights in May 2024 alone.

United Airlines’ strategy reflects its commitment to expanding and modernizing its fleet, ensuring it remains a key player in the competitive airline landscape.