American Airlines maintains its position as the world’s largest airline by frequency, operating 189,100 flights this month, 39,900 more than Delta Air Lines, which ranks second by this measure, according to OAG data.
Among the major carriers, United Airlines is showing the strongest year-over-year growth in flight frequency, adding 10,500 more flights than April last year. American Airlines closely follows, with an increase of 10,200 flights.
IndiGo continues to lead in terms of growth rate, expanding its flight frequency by 13% year-over-year, making it the fastest-growing airline globally. In contrast, Deutsche Lufthansa AG has recorded the steepest decline, with a 7.3% reduction in frequency compared to last year.
Domestic Markets: The U.S. and India Lead in Size and Growth
OAG data also showed that the United States remains the world’s largest domestic aviation market, with 88.4 million seats scheduled this month, 19.8 million more than China, which holds the second spot with 68.5 million seats.
India is the fastest-growing domestic market among the global Top 10, with 9.7% growth over the past year. Mexico follows closely, expanding by 9.1%. On the flip side, Indonesia has experienced the sharpest decline among top domestic markets, with a 9.9% decrease, continuing a downward trend seen last month. Other domestic markets in decline include Spain (-2.8%), Australia (-1.4%), and Turkey (-1.1%).
Global Aviation Outlook: Steady Growth and Regional Trends
Global airline capacity in April 2025 is projected to reach 501.6 million seats, a 4% increase compared to April 2024. This translates to an additional 20.8 million seats year-over-year, according to OAG.
North America is the largest region by seat capacity, with 110.2 million seats, followed closely by Northeast Asia at 108.6 million. Western Europe has seen the biggest absolute increase in capacity, adding 4.2 million seats for a total of 105.4 million, year-over-year.
In terms of growth rate, Central Asia (16%) and North Africa (11%) lead all regions. The only region experiencing a decline is Central/Western Africa, where seat capacity is down 5.7% from last year.
