The transatlantic flight market between the United States and Spain is experiencing remarkable growth, with a **16% increase** in scheduled flights for December 2025. According to data from **Cirium**, an aviation analytics firm, there will be **1,724 flights** connecting the two nations, up from **1,486** in December 2024. This surge in activity has also led to a **14.9% rise** in seat capacity, reflecting a trend towards using smaller aircraft on certain routes.
Iberia Dominates the Market
Spanish flag carrier **Iberia** leads the way in this expanding market, providing the highest number of flights and seats. The airline plans to operate **732 flights** this December, accommodating **205,592 passengers**. These figures mark significant increases of **32.6%** in flights and **25.9%** in seat capacity compared to the previous year. The top route for Iberia is between **Madrid (MAD)** and **New York (JFK)**, featuring two daily round trips. Other notable destinations from Madrid include **San Juan (Puerto Rico)** with **48 rotations**, **Boston** at **46**, and **Miami** with **44 flights**.
Iberia primarily utilizes widebody aircraft from the Airbus A330 family for its long-haul operations. However, the introduction of the **Airbus A321XLR** has been a game-changer, enabling the airline to expand its East Coast operations significantly. **Ramiro Sequeira**, Iberia’s Chief Production Officer, commented last month, “The Airbus A321XLR has transformed our long-haul strategy, enabling us to open new destinations and increase frequencies with unprecedented efficiency.”
American and Delta Make Strides
On the other side of the Atlantic, **American Airlines** maintains a strong presence in the US-Spain market with **432 flights** scheduled for December 2025, consistent with last year’s figures. Despite the same number of flights, the airline has increased its seat capacity by **5.7%**, indicating a shift to larger aircraft or more efficient cabin layouts. American Airlines operates primarily Boeing 777 and 787 aircraft, with daily flights from Madrid to JFK, as well as to **Charlotte (CLT)**, **Dallas/Fort Worth (DFW)**, **Miami (MIA)**, and **Philadelphia (PHL)**.
**Delta Air Lines** is also expanding its operations, reporting a **20.2% increase** in flights, rising from **213** in December 2024 to **256** this year. Delta utilizes a mix of aircraft, including **62 flights** with the Airbus A330-300 and **194** with the Boeing 767-400ER. Key routes include **Atlanta (ATL)** to **Barcelona** and **Madrid**, both featuring **35** and **31 round trips**, respectively.
Other Notable Carriers
**United Airlines**, the last of the major US legacy carriers, has scheduled **197 flights** between the US and Spain this month, representing an **8.8% increase** over the previous year. United operates a fleet comprising Boeing 767, 777, and 787 aircraft, offering daily flights from **Newark (EWR)** to Madrid and Barcelona, alongside lower frequency flights from **Washington (IAD)** and **Chicago (ORD)**.
The final airline operating scheduled passenger flights between the US and Spain is **Air Europa**, which has slightly reduced its offerings from **108** to **107 flights** this year. Most of Air Europa’s services utilize Boeing 787 aircraft, with some flights operated by Iberojet using Airbus A330-900s. The airline provides direct connections from Madrid to Miami and JFK.
This surge in flights and seat capacity between the United States and Spain highlights the ongoing demand for transatlantic travel, underscoring the importance of this route for both leisure and business travelers. As airlines adapt their strategies and expand their offerings, passengers can expect even more options in the coming months.
