The Big 3: Which Airline Operates The Youngest Fleet?

Published Aug 21, 2026, 1:00 PM EDT Louis is a military historian and the staff writer for History of War magazine, a leading military history monthly. He also has an interest in private and commercial aviation. Each of America's big three legacy carriers, United Airlines, Delta Air Lines and American Airlines, has a similarly aged fleet. However, there are some differences. United has the oldest fleet at 15.1 years average aircraft age. Delta is close behind at 15 years. Finally, American has the youngest fleet with an average aircraft age of 14.7 years. Please note that the data included in this article includes only the mainline fleet for each carrier, discounting the jets owned or operated by their regional subsidiaries. In years to come, we can expect the balance to shift. United has a far larger order sheet than its rivals. Once these new aircraft arrive, it could leapfrog both of them to have the youngest fleet in the United States' legacy aviation. American and Delta could both drop a single place as a result. United Airlines Has The Oldest Fleet Credit: Shutterstock United has a marginally older fleet than its rivals with an average age of 15.1 years. Unsurprisingly, its newest widebody aircraft belongs to the newest aircraft family it owns: the Boeing 787. The Airbus A350 is notable in its absence. United also operates an exceptionally young Airbus A321 family. The firm has plans to introduce the Coastliner Airbus A321neo. These jets will exclusively fly transcontinental routes between hubs in cities like Los Angeles, San Francisco and New York. With 50 Coastliners on order and 40 to be delivered by April 2028, the A321 is sure to remain an exceptionally young family in its fleet. The table below uses Planespotters.net data to reveal the average age of each jet in United's current fleet: Aircraft Type In Service Parked Current Total Avg. Age Airbus A319 67 6 73 24.6 Years Airbus A320 63 3 66 26.4 Years Airbus A321 72 1 73 1.3 Years Boeing 737 591 28 619 11.9 Years Boeing 757 58 3 61 27.6 Years Boeing 767 49 4 53 28.8 Years Boeing 777 83 13 96 23.0 Years Boeing 787 Dreamliner 90 1 91 7.1 Years Total 1,073 59 1,132 15.1 Years Meanwhile, the oldest jet in United's fleet is the 777. United is the world's second-largest operator of this aircraft. It also has a substantial fleet of 777-200s and the world's largest -200ER fleet. The 777 will likely remain United's oldest aircraft family for years to come. That is because United, along with every other carrier in the United States, has failed to order the Boeing 777X. Delta Air Lines Is In The Middle Credit: Shutterstock Delta's 15-year-old fleet is in the middle of the big three in terms of age. Its youth is driven by an exceptionally young and large fleet of Airbus A220 and A321 family aircraft. It regularly flies its A220 on busy domestic corridors. Examples include New York LaGuardia Airport (LGA) to Dallas/Fort Worth International Airport (DFW) and Salt Lake City International Airport (SLC) to John Wayne Airport (SNA) in Santa Ana, California. In terms of widebody aircraft, Delta has a new and young fleet of A350s. This fleet has focused on the Airbus A350-900. However, the carrier is targeting the arrival of its first Airbus A350-1000 in June 2027. It has a total order of 20 of these jets. The table below uses Planespotters.net data to reveal the average age of each jet in Delta's current fleet: Aircraft Type In Service Parked Current Total Avg. Age Airbus A220 85 4 89 4.7 Years Airbus A319 55 2 57 24.5 Years Airbus A320 41 1 42 29.2 Years Airbus A321 225 3 228 5.3 Years Airbus A330 79 2 81 11.5 Years Airbus A350 XWB 40 1 41 5.8 Years Boeing 717 75 2 77 24.8 Years Boeing 737 236 4 240 15.2 Years Boeing 757 84 4 88 27.4 Years Boeing 767 55 2 57 28.0 Years Total 975 25 1,000 15 Years Delta operates an enormous variety of aircraft families. The oldest narrowbody jet is the A320 at almost 30 years. Despite this jet's age, Delta has still been able to incorporate premium seating. It configures the aircraft with 157 passengers. Sixteen are in the first class cabin, with a further 18 in Delta Comfort+. The remaining 123 passengers sit in the main cabin. American Airlines Has The Youngest Fleet Credit: Shutterstock American boasts the youngest fleet among the big three. It has an average aircraft age of just 14.7 years, with a larger fleet than Delta, but slightly smaller than United. American doesn't have the same degree of exceptionally young aircraft as its rivals. Its youngest is the 787 at 7.3 years. This jet is an ideal fit for the carrier's transatlantic and transpacific routes. Yet, the carrier also has a much lower maximum average aircraft age than United and Delta. Its oldest aircraft family, the A320, barely reaches 25 years old, with just 48 jets in this family. The table below uses Planespotters.net data to reveal the average age of each jet in American's current fleet: Aircraft Type In Service Parked Total Avg. Age Airbus A319 122 10 132 22.4 Years Airbus A320 48 None 48 25.4 Years Airbus A321 303 7 310 11.4 Years Boeing 737 397 9 406 13.5 Years Boeing 777 65 2 67 21.8 Years Boeing 787 Dreamliner 70 None 70 7.3 Years Total 1,005 28 1,033 14.7 Years The reason for its fleet's low average age is the vast quantity of narrowbody aircraft in families under 15 years old on average. The carrier has 303 A321s averaging 11.4 years and 397 737s averaging 13.5 years. The youthfulness of the 737 family is driven by the arrival of Boeing 737 MAX aircraft, while jets like the A321XLR are causing American's Airbuses to also drag the average age down. Order Sheets Show That The United Fleet Is About To Get Much Younger Credit: Shutterstock Little is certain in the aviation industry, except that aircraft will be purchased new and get older with each year that passes, until they are inevitably forced into retirement or the cargo industry. As a result, just because American Airlines has the youngest fleet now, does not mean that will always be the case. In fact, over the next several years, we will see the tables flip, with United gaining the youngest fleet. With an order sheet of 69 aircraft, there will be far more new aircraft coming into its ownership than its rivals. American has 12 orders and Delta just 16. United calls its fleet renewal program United Next, whereby it hopes to add 250 new planes by 2028. These efforts will replace many of the jets that have led United to have such an old fleet. For example, the A321XLR will replace the Boeing 757 on routes to smaller cities in Europeand South America. These planes will be fitted with United Polaris seats, part of the goal to create a widebody experience on narrowbody aircraft. The table below uses Planespotters.net data to show the orders for various narrowbody and widebody aircraft for each of the big three legacy airlines: Aircraft American Orders Delta Orders United Orders Airbus A321 20 14 27 Boeing 737 None None 36 Airbus A350 None 2 None Boeing 787 1 None 6 Total 21 16 69 "For more than a decade, we've invested billions of dollars in our product, service, and technology as part of our plan to be the best brand loyal airline in the world, and the result is that more and more customers are choosing to fly us every day," said United CEO Scott Kirby, as reported by PR Newswire. "Today we accelerate our plans and elevate our offerings to the next level." American Continues To Pioneer The Introduction Of New Aircraft To United States Aviation Credit: Shutterstock | Simple Flying United Next will be transformative in the years to come, while American is already changing the nation's aviation industry by bringing certain aircraft into the country for the first time. American became the first US airline to receive an A321XLR in October 2025, as reported by the carrier. It flew the inaugural flight from New York to Los Angeles that December. Designed for long journeys with comfort and style at the forefront, American is thrilled to be the first US airline to operate the A321XLR,” said Heather Garboden, American’s Chief Customer Officer. “Whether customers are traveling from coast to coast or across the ocean, American’s newest aircraft demonstrates our commitment to providing a premium travel experience.” The importance of the A321XLR for US aviation will become increasingly clear as airlines retire their outdated widebody planes. The A321XLR offers an alternative way to fill capacity gaps, particularly on niche routes that would usually be too long for a narrowbody aircraft to cover. Before the arrival of the A321XLR, American had faced embarrassing capacity issues after retiring aircraft like the Boeing 767-300ER in 2020. The moves created a shortage of widebody aircraft in American's fleet. Problems arose after passenger numbers bounced back faster than expected following the lifting of pandemic-era restrictions. It had to reluctantly shrink its long-haul network, notably moving away from certain smaller secondary destinations.