Heathrow is London's main full-service global hub, with a dense mix of long-haul, European and domestic services.
Network
Heathrow serves destinations across roughly 80 countries and is the UK's strongest airport for intercontinental connectivity. Long-haul traffic to North America, Asia, the Middle East and Africa sits alongside a dense European and domestic network.
Major airlines
British Airways has its principal hub at Heathrow. Other major operators include Virgin Atlantic and a broad set of global network airlines such as American, United, Air Canada, Lufthansa-group carriers, Air France, KLM, Emirates, Qatar Airways, Singapore Airlines, Cathay Pacific, ANA and many others. Because the roster changes, use Heathrow's live airline directory rather than treating a static list as exhaustive.
Terminals matter
Airlines and even routes from the same airline can use different terminals. Check the airport's Which terminal? tool before travelling and see Terminals.