London Heathrow Airport

London Heathrow is Europe's busiest airport by passenger traffic (79.2M in 2024) and one of the most slot-constrained major airports in the world — its two parallel runways run at 98% of theoretical capacity, which is why a third runway has been debated politically for over four decades without construction ever starting. Every takeoff and landing slot is a financial asset, with peak-hour pairs trading on a secondary market for tens of millions of pounds. British Airways operates its global hub from Terminal 5, which handles the airline's entire long-haul fleet and most of its short-haul European network. Virgin Atlantic anchors Terminal 3 alongside a dense oneworld presence (American, Qatar, Cathay Pacific, JAL); Terminals 2 and 4 serve Star Alliance and SkyTeam partners respectively. Heathrow is the primary European gateway for North American carriers — almost every legacy U.S. airline runs multiple daily transatlantic departures here. The airport's international connectivity is exceptional: 203 direct destinations reached by 84 airlines, one of the highest airline counts anywhere. Its geographic position 24 km west of central London, combined with Heathrow Express and the Elizabeth Line's fast rail links, make it the default airport for business travel to the UK despite competing with Gatwick, Stansted, Luton, and City within a 60-mile radius. Terminal 2 (opened 2014) and Terminal 5 (opened 2008) together represent the largest capital expansion project in British aviation history.