Copyright Simple Flying
American Airlines and Delta Air Lines are the two largest carriers in the US by several measures, including passenger numbers and fleet size. The two airlines go head-to-head on many routes, although the majority of their hubs are found at different airports. However, both American Airlines and Delta Air Lines have recently expanded further into each other's territory, increasing competition on key transcontinental routes. In this article, we take a closer look at the new and expanded routes where American Airlines and Delta Air Lines are set to go head-to-head, highlighting the intensifying competition on key domestic corridors. We will also explore the carriers’ broader route networks, examining how their strategies fit into the wider commercial aviation landscape across the US. Delta Air Lines' New Transcontinental Service To Philadelphia Delta Air Lines has confirmed plans to launch a new non-stop route from its Seattle-Tacoma International Airport (SEA) hub to Philadelphia International Airport (PHL). Scheduled to begin in May 2026, the service will see Delta Air Lines enter a market already served by both American Airlines and Alaska Airlines. This controversial move highlights Delta Air Lines' ongoing strategy to strengthen its domestic network and expand beyond its traditional strongholds on the West Coast, offering passengers more options for transcontinental flights. It is likely to intensify competition on the route, putting pressure on fares and schedules. American Airlines in particular is also likely to be upset at this news, given that Philadelphia International Airport is one of the carrier's major East Coast hubs, from where it operates a variety of domestic and international routes. The oneworld carrier operates two daily flights in each direction between Seattle-Tacoma International Airport and Philadelphia International Airport - one with the Boeing 737 MAX 8 and one with the Airbus A321neo. Delta Air Lines will also deploy its Airbus A321neos on this new route. The latest data from ch-aviation shows that the SkyTeam carrier currently operates a total of 84 A321neos, with a further 71 on order. The narrowbody aircraft plays just a small part in Delta Air Lines' staggering fleet of over 900 aircraft, which is set to grow as new aircraft join the fleet, although some will be used to replace the carrier's aging aircraft. Delta Air Lines' fleet is outlined in the table below: American Airlines Upgrades Its Salt Lake City Service Just a few days after Delta Air Lines announced its latest route between Seattle-Tacoma International Airport (SEA) and Philadelphia International Airport (PHL) in October 2025, American Airlines upgraded its service between Philadelphia International Airport and Salt Lake City International Airport (SLC) from seasonal to year-round. American Airlines will operate one daily flight in each direction between the two cities, deploying its Airbus A321s on the route, while Delta Air Lines serves the route twice daily, also with its fleet of A321s. How does American Airlines' fleet compare to that of Delta Air Lines? The oneworld carrier's mainline fleet is slightly larger, with just over 1,000 aircraft in total, and American Airlines also has a greater number of aircraft on order, signaling strong growth and fleet modernization to come over the next few years. The carrier's fleet is outlined in the table below: Further Network Expansion From American Airlines In addition to its extended service between Philadelphia International Airport (PHL) and Salt Lake City International Airport (SLC), American Airlines also took the opportunity to announce four new routes from its hubs at Charlotte Douglas International Airport (CLT) and Chicago O'Hare International Airport (ORD) that will be operated by its regional subsidiary, American Eagle. These new routes are listed in the table below: SkyWest Airlines will operate the flights on behalf of American Eagle with its fleet of Bombardier CRJ700 and Embraer 175 aircraft. American Airlines' Imminent Return To Israel Another route on which American Airlines will go head-to-head with Delta Air Lines is between New York John F. Kennedy International Airport (JFK) and Tel Aviv Ben Gurion Airport (TLV). The oneworld carrier recently announced its plans to resume its daily flights to Tel Aviv from March 2026, although there has been no word yet on its previous services from both Dallas/Fort Worth International Airport (DFW) and Miami International Airport (MIA). In addition to facing up to Delta Air Lines, American Airlines will also face significant competition from El Al and Arkia, as well as United Airlines, which is set to offer up to three daily flights to Tel Aviv Ben Gurion Airport from its hub at Newark Liberty International Airport (EWR), as well as routes from Chicago O'Hare International Airport (ORD) and Washington Dulles International Airport (IAD). In 2024, New York John F. Kennedy International Airport was the fifth-busiest international destination and sixth-busiest overall from Tel Aviv Ben Gurion Airport, seeing more than 529,000 passengers across all carriers. The five busiest destinations are shown in the table below: Delta Air Lines At Seattle-Tacoma International Airport (SEA) Delta Air Lines has steadily grown its presence at Seattle-Tacoma International Airport (SEA) over the years, transforming the airport into one of its key West Coast hubs. Traditionally dominated by Alaska Airlines, the airport has become a strategic foothold for the SkyTeam carrier as it seeks to expand its domestic, transcontinental, and transpacific network. Delta Air Lines' expansion at Seattle-Tacoma International Airport seems to be part of a broader strategy to challenge Alaska Airlines’ dominance in the Pacific Northwest. Recent announcements, including the new non-stop service to Philadelphia International Airport starting in May 2026, underline the carrier's somewhat aggressive approach to capturing market share on routes historically dominated by competitors. For passengers, more competition on a route is often a good thing, bringing with it lower fares as airlines battle it out to win over customers. Delta Air Lines' presence at Seattle-Tacoma International Airport also opens the facility up to SkyTeam connections worldwide through partner airlines such as Korean Air, Aeromexico, China Eastern Airlines, and Air France. Delta Air Lines' five busiest routes from Seattle-Tacoma International Airport in terms of the number of flights operated in November 2025 are shown in the table below, according to data from Cirium, an aviation analytics company: American Airlines At Philadelphia International Airport (PHL) American Airlines has long considered Philadelphia International Airport (PHL) to be one of its core hubs, using it as a gateway to connect the northeastern US with a wide variety of domestic and international destinations. As the largest carrier at the airport, American Airlines commands a 47% market share and operates hundreds of daily flights, serving key US cities, as well as an increasing number of destinations across the Caribbean and Europe, including London Heathrow Airport (LHR), Paris Charles de Gaulle Airport (CDG), and Amsterdam Schiphol Airport (AMS). American Airlines' strategy at Philadelphia International Airport focuses on both volume and connectivity, with the carrier's extensive domestic network allowing passengers to connect seamlessly to and from international flights. Passengers also benefit from access to American Airlines' oneworld partner airlines, such as Cathay Pacific, Qantas, Japan Airlines, and British Airways. American Airlines' investment at the airport also extends beyond its flying operation, having invested in terminal modernization and lounge upgrades. Philadelphia International Airport's strategic location on the East Coast allows the carrier to capture a wide range of both business and leisure travel, with many passengers seeing it as a less-congested alternative to the busy airports of the New York City area. American Airlines' five busiest routes from Philadelphia International Airport in terms of the number of flights operated in November 2025 are shown in the table below: It remains to be seen what lengths American Airlines and Delta Air Lines will go to in order to protect their respective hubs at Philadelphia International Airport and Seattle-Tacoma International Airport, but it will certainly be interesting to see how each carrier responds to the increase in competition over the coming weeks and months.
