British Airways is the largest airline in the UK based on fleet size, international flights and international destinations and second largest measured by passengers carried, behind easyJet.

In 2026, the title of "biggest airline in the UK" depends on whether you measure by fleet size or passenger numbers. By total passengers carried, the low-cost giant easyJet remains the largest UK-based airline, transporting over 80 million people annually across its massive European network. However, British Airways (BA) remains the UK's "flag carrier" and the largest in terms of fleet size and long-haul revenue, operating out of its primary hub at London Heathrow. If you look at the total "UK aviation market share" including non-UK carriers, the Irish airline Ryanair actually carries more passengers to and from the UK than any other airline, reaching a record-breaking 207 million passengers globally in 2026. For a UK-bound traveler, easyJet and British Airways are the "Big Two," with easyJet dominating short-haul leisure routes and British Airways serving as the premier choice for global business and transatlantic travel. The competition between these two is fierce, with both airlines recently breaking pre-pandemic records in 2025 as UK aviation surpassed 300 million total passenger journeys for the first time in history.