How seasonal trends affect transatlantic flight strategies at major US airlines

Among US carriers operating long-haul international flights, United Airlines leads with the highest number of flights to Asia, Oceania, and Europe. American Airlines has a stronger position in South America while Delta Air Lines holds a leading share of US-to-Africa flights. Across all three airlines, transatlantic capacity peaks in July and August before dropping sharply around January—a pattern that affects each carrier’s market share throughout the year.

United Airlines and Delta Air Lines tend to redeploy widebody jets domestically or on nearby international routes during periods of low transatlantic demand. These adjustments help meet increased interest in winter travel hotspots like Florida or Caribbean destinations. As a result, there is an inverse relationship between widebody deployment on European versus North American routes for both carriers.

Flight activity by United and Delta remains steady across Asian, South American, and Oceanian markets regardless of seasonality; however, United is expanding its presence in Asia through fifth-freedom flights from Tokyo Narita using Boeing 737s. Delta recently announced plans for a Los Angeles–Hong Kong route set for next June—a move that will see it compete directly with United’s established service on that corridor.

United Chief Scott Kirby commented about this competition: "Delta will 'lose money' on the route," as reported earlier this month.

American Airlines faces more challenges internationally due to limited aircraft availability and past reductions in service to key regions such as Asia and South America. The airline lost ground after LATAM Airlines chose a partnership with Delta instead of renewing ties with American; LATAM’s capacity was not replaced by additional American-operated aircraft.

Unlike its rivals’ counter-cyclical strategy with widebodies between North America and Europe during off-peak seasons, American does not shift significant capacity back home but instead redirects resources toward South America during Europe’s winter months.

This overview focuses primarily on widebody operations; narrowbody contributions were not included but remain important within each carrier's broader network strategy.

"Delta will 'lose money' on the route," said United Chief Scott Kirby.

The ongoing shifts raise questions about whether American will continue trailing its competitors or pivot further towards domestic opportunities.