Top 10 Busiest US Airlines and Airports

25-12-2025   |   Posted By: Aditya Singh   |   91 View(s)

OAG has just come out with its annual analysis of the Aviation Trends across the World and here are the stats related to the Busiest Airlines of United States of America in terms of Seats.This throws up interesting trends in which the American Airlines has emerged as the Number  One Airline of USA.Here goes the complete List.Enjoy!

Here are some highlights from this month’s US market data:

Largest airline: American Airlines (21.3m seats)
Busiest airport: Atlanta Hartsfield-Jackson (5.2m seats)
Busiest US domestic flight route: New York JFK to Los Angeles (302,700 seats)
State adding most airline capacity: Florida (+371,700 seats)

The Ranking of the Top Ten US Airlines is as under:

1. American Airlines ~21.3 million (Dec 2025) Largest U.S. airline by seats; ~21% market share
2. Southwest Airlines ~19.3 million (Dec 2025) ~19% market share; largest low-cost carrier

3. Delta Air Lines ~18.8 million  ~18% market share

4. United Airlines ~16.8 million – Fourth largest in  2025

5. Alaska Airlines ~4.94 million – Fifth in  2025 capacity

6. JetBlue Airways ~3.58.0 million † Strong leisure and domestic network

7. Frontier Airlines~3.5 million † Low-cost carrier in expanding role

8. Spirit Airlines ~2.47 million † Major ultra-low-cost carrier

9. Allegiant Air ~2.04 million † Niche leisure routes

10. Hawaiian Airlines ~1.15 million † Island-focused carrier

American Airlines remains the biggest carrier in the US in December 2025 with 21.3m scheduled airline seats, which represents 21% of the market.
Southwest Airlines and Delta Air Lines represent 19% and 18% share of the market respectively, with 19.3m and 18.8m scheduled airline seats.
Spirit Airlines decreased capacity by 33% vs December 2024, with 1.24m fewer scheduled airline seats.
The Big 4 (American, Delta, United, and Southwest Airlines) represent 74% of the total US market.

New York JFK to Los Angeles is the busiest route in the US this month, with 302,700 seats available – an 8% increase in capacity compared to December 2024.
The Atlanta to New York LaGuardia route saw the largest percentage growth this month, with capacity rising 15% to 250,400 seats.
Seat capacity saw the largest decreases on the Las Vegas to Los Angeles route (down 14%) and the Honolulu to Kahului route (down 13%) compared to December 2024.
Honolulu to Los Angeles has displaced Los Angeles to Chicago in the Top 10 rankings, taking it to 11th position.

Top 10 Busiest U.S. Airports — 2025 (Seat Capacity)

1 .ATL Hartsfield–Jackson Atlanta Intl Apt ~38.0 million (summer seats) Atlanta remains the busiest U.S. airport by seat capacity in 2025.

2. DFW Dallas–Fort Worth Intl

3.ORD Chicago O’Hare International Apt ~31.3 million

4. DEN Denver International Airport. Known major U.S. hub; often top-ranked by capacity.

5. LAX Los Angeles International Airport .Among the nation’s busiest airports.

6. JFK John F. Kennedy International Airport .Listed within top 10 busiest U.S. airports.

7. MCO Orlando International Airport. Also in the national top 10 busiest.

8. MIA Miami International Airport. Ranked top 10 based on passenger traffic.

9.PHX Phoenix International Airport.Ranked top 10 based on passenger traffic.

10. LAS Harry Reid International Airport. Ranked among busiest U.S. airports.

Atlanta (ATL) is the busiest U.S. airport in 2025 by scheduled seat capacity, with around 38 million seats in summer 2025 which is followed by Dallas Fort Worth International Airport.
Chicago O’Hare (ORD) ranks Third in summer seat capacity with about 31.3 million seats.

The remaining airports in this list are generally recognized among the top 10 busiest airports in the U.S. by seat capacity and passenger traffic in 2025 — based on OAG market data and corroborating listings.

Credit:OAG