The flight market between the United States and Spain has experienced remarkable growth, with a projected **16% increase** in scheduled flights for December 2025 compared to the previous year. According to aviation analytics firm **Cirium**, a total of **1,724 flights** are set to operate between the two nations, rising from **1,486 flights** in December 2024. This surge in flights has also led to an increase in seat capacity, which is up **14.9%**, reflecting a strategic shift by airlines to utilize smaller aircraft to meet rising demand.
Iberia Leads the Market
Spanish flag carrier **Iberia** commands the largest share of the transatlantic market, with **732 flights** and **205,592 seats** scheduled for December 2025. These figures represent substantial year-on-year increases of **32.6%** in flights and **25.9%** in seat capacity compared to December 2024, when Iberia operated **552 flights** and provided **163,274 seats**. The route from **Madrid (MAD)** to **New York (JFK)** remains Iberia’s primary connection, featuring two daily round trips. Other significant routes include frequent services to **San Juan, Puerto Rico**, **Boston**, and **Miami**.
Iberia has incorporated the **Airbus A321XLR** into its operations, accounting for **220 flights**, which has enabled the airline to expand its East Coast offerings. Ramiro Sequeira, Iberia’s Chief Production Officer, emphasized the aircraft’s impact: “The Airbus A321XLR has transformed our long-haul strategy, enabling us to open new destinations and increase frequencies with unprecedented efficiency.”
American Airlines and Delta Air Lines Expand Services
On the American side, **American Airlines** maintains a substantial presence with **432 flights** scheduled for December 2025, consistent with the previous year’s figures. However, seat capacity has grown by **5.7%**, indicating the use of larger aircraft or denser cabin configurations. The airline primarily operates widebody jets from the **Boeing 777** and **787** families on its Spanish routes. American continues to serve the **Madrid to JFK** route daily, alongside key connections to **Charlotte**, **Dallas/Fort Worth**, and **Miami**.
**Delta Air Lines** has achieved the most significant growth among U.S. carriers, increasing its flight schedule by **20.2%** from **213 flights** in December 2024 to **256 flights** this year. Delta operates a mix of **Airbus A330-300** and **Boeing 767-400ER** aircraft, with notable routes including **Atlanta (ATL)** to **Barcelona (BCN)** and **Madrid**, each featuring 31 round trips per week.
**United Airlines**, while not as dominant as its competitors, has also expanded its operations, scheduling **197 flights** in December 2025, an **8.8%** increase from the previous year. United’s fleet includes **Boeing 767**, **777**, and **787** aircraft, connecting **Newark (EWR)** with both Madrid and Barcelona, along with lower frequency routes from **Washington (IAD)** and **Chicago (ORD)**.
Lastly, **Air Europa**, a Spanish carrier, is maintaining its presence with **107 flights** scheduled, slightly down from the **108** flights in December 2024. Most of these services utilize **Boeing 787s**, with some operations supported by **Iberojet** using **Airbus A330-900s**.
The growth in the transatlantic flight market between the United States and Spain reflects the increasing demand for air travel and the strategic responses from airlines to capitalize on this trend. As more options become available, passengers can look forward to enhanced connectivity and more competitive pricing in the months ahead.