Heathrow Airport in London is the UK's largest and busiest airport as well as being the busiest airport in Europe and the seventh busiest in the world based on passenger traffic.

London Heathrow Airport (LHR) is officially the busiest airport in the United Kingdom and currently holds the title of the busiest hub in Europe. In 2025, Heathrow welcomed a record-breaking 84.5 million passengers, surpassing its pre-pandemic highs. Projections for 2026 indicate an even higher volume, with the airport on track to handle approximately 85 million passengers. Heathrow serves as the primary global gateway for the UK, hosting over 80 airlines and connecting to more than 200 destinations worldwide. It operates at nearly 98% of its runway capacity, which has driven the long-standing and complex debate regarding the construction of a third runway. While other UK airports like Gatwick (LGW) and Manchester (MAN) handle significant traffic—Gatwick often serving over 40 million passengers annually—Heathrow remains the dominant force in British aviation, accounting for a vast majority of the country's long-haul and business travel.