Book flights from Heathrow: the practical guide

Aggregators are useful for discovery. Skyscanner, Google Flights, and Kayak surface routes, fare ranges, and flexible-date views you cannot get from a single airline site. They are the right starting point when you do not yet know which carrier serves the route, or when the dates are negotiable.

The booking itself is usually safer direct with the airline. When a flight is cancelled, the schedule changes, or you need to re-route, the airline being the merchant of record is the cleaner path. Third-party booking sites add a layer that has to be worked through before the airline can act, and the £5 to £20 you might save on the headline fare is rarely worth losing the airline as a single point of contact when something goes wrong. The exception is package holidays, which carry their own protections under the Package Travel Regulations. For the cluster around this page, the Flight information hub is the parent.

Heathrow's value at booking time is network depth. The airport serves 230 destinations on more than 80 airlines, the deepest international network of any UK airport, with the widest choice of carriers and frequencies to the US, Asia, the Middle East, and Africa. For most long-haul routes from London, Heathrow has more flights, more carriers, and more frequencies than the other London airports combined.

The other London airports are honest competitors on specific lanes. Gatwick is genuinely strong on transatlantic leisure (British Airways, Norse, JetBlue, Delta), parts of the Caribbean, and a slice of Asia (TUI long-haul). Stansted, Luton, and Southend dominate short-haul Europe on the budget carriers (Ryanair, easyJet, Wizz Air, Jet2). London City wins on time-sensitive short-haul business travel inside Europe and to a handful of leisure routes. The right choice is the airport that matches the route, the fare, and where the journey starts, not the airport closest to home by default. For UK government guidance on destination-side rules (visas, entry, safety), gov.uk foreign travel advice is the canonical source.

Your terminal at Heathrow is set by the airline you choose at booking, not by the destination. The four operating terminals are grouped by alliance: Terminal 2 hosts most of Star Alliance (Lufthansa, United Airlines, Singapore Airlines, ANA, Air Canada), Terminal 3 hosts most of oneworld (American Airlines, Cathay Pacific, Japan Airlines, Qantas) plus Virgin Atlantic and Delta, Terminal 4 is the SkyTeam base (Air France, KLM, Korean Air) plus Qatar Airways and Etihad, and Terminal 5 is British Airways and Iberia only.

A handful of edge cases break the heuristic: Aer Lingus stayed at T2 when it rejoined oneworld in April 2025, ITA Airways moved to T2 in March 2026 ahead of joining Star Alliance, and Virgin Atlantic remains at T3 despite being a SkyTeam member. Codeshare flights depart from the operating carrier's terminal, not the marketing carrier's, which catches out travellers who booked a BA-numbered flight that is actually flown by Aer Lingus from T2. Airlines flying from Heathrow has the full per-carrier table; Heathrow's terminal finder resolves it by airline name when the boarding pass is not yet to hand.

Heathrow's network depth means most major long-haul destinations have a direct option from the airport. The premium-cabin gravity at Heathrow also keeps the gap between a direct flight and a one-stop connection narrower than at smaller European hubs, particularly on US and Gulf routes where the direct carriers compete hard for the same business travellers. The genuine savings tend to sit on routes Heathrow does not serve directly, where a one-stop via Amsterdam, Paris, Frankfurt, or Istanbul opens up cheaper options.

Self-connections on separate tickets save the most money but cost you the through-checked baggage and the airline's responsibility if the first flight is late. For a self-connection at Heathrow itself you also need to clear UK immigration on the first arrival, collect bags, re-check in at the next airline's desk, and re-clear security like any other departing passenger. Allow at least 3 hours plus the time to move between terminals; connecting flights at Heathrow covers the minimum connection times for through-checked single-ticket connections, which are different.

There is no magic booking window. Rough patterns: short-haul European fares are often cheapest 6 to 8 weeks out, long-haul typically 3 to 5 months out. School holidays, Christmas, summer peaks, half-term, and major events all break the pattern, sometimes sharply; specific routes break it differently in different years. Fare-alert tools on the aggregators are a better signal than any single rule of thumb.

A useful step before chasing fares is to confirm a route exists at all. Heathrow's year-ahead schedule tool at heathrow.com/flight-timetable lists every scheduled flight up to 12 months ahead by date, airline, route, and aircraft type. The tool is the public-facing slice of the airport's published schedule and confirms whether a destination is served from Heathrow at all before the comparison sites narrow down on fare.

Several Heathrow add-ons are meaningfully cheaper booked ahead than on the day, and the moment you finalise the flight is the right time to lock them in. The Heathrow Express to Paddington drops from £25 walk-up to £10 advance on the same train. Parking is the largest gap of any add-on: Park & Ride is around £46.80 a day on arrival versus £11 to £15 a day booked ahead through Heathrow's own site. Fast Track security can be pre-booked from £12.99 per person, useful at the morning long-haul peak and the late-afternoon European outbound peak. Most airport lounges accept pre-booking through Priority Pass or the operator's own site. None of these need to be booked the same day as the flight, but adding them as the trip firms up is cheaper than scrambling later. Heathrow departures and what to do before you fly covers the practical sequence on the day.

UK261 (the UK version of the EC261 framework retained after Brexit) sets out the rights of air passengers in the UK. It applies to any flight departing a UK airport regardless of which airline operates it, and to flights into the UK on a UK or EU carrier. A Heathrow departure is covered whether you fly British Airways, Emirates, Delta, Singapore Airlines, or any other carrier. The Civil Aviation Authority enforces the rules.

If the airline cancels the flight, you have a choice of three remedies. You can take a full refund of the unused part of the ticket, payable within 7 days. You can take an alternative flight to the destination at the airline's expense, at the earliest opportunity. Or you can re-route at a later date of your choice, subject to seat availability. The airline must offer the choice; it cannot impose a refund on you or impose a re-booking on you.

If the cause was within the airline's control and notification of a cancellation was late, fixed-sum compensation also applies on a CAA distance-banded scale. The figures have not changed since UK261 was retained after Brexit:

• Short-haul, under 1,500km: £220
• Medium-haul, 1,500 to 3,500km: £350
• Long-haul, over 3,500km: £520

The compensation right is triggered when you reach your destination more than 3 hours late and the cause is within the airline's control (mechanical issues, crew shortages, airline strikes). Extraordinary circumstances such as severe weather, air-traffic control strikes, or political instability remove the compensation right but not the refund or re-routing right.

While you wait, the airline must provide care. The CAA care thresholds are 2 hours for short-haul, 3 hours for medium-haul, and 4 hours for long-haul. Care covers food, drink, communication (typically two phone calls or equivalent), and overnight accommodation with transport to and from the hotel if needed. A delay of 5 hours or more gives a separate right to a refund even if you choose not to travel.

Package holiday bookings carry additional protection under the UK Package Travel Regulations, layered on top of UK261. For the full treatment, see your rights when a flight is cancelled; the authoritative public source is the CAA passenger rights pages.

If you are already at the airport when the cancellation lands, the airline's desk is the first stop. The airline's priority is rebooking, not refunding, so you usually get a rebooked flight faster by approaching the desk in person than by waiting on the app. Ask for written confirmation of any rebooking, refund offer, or care provided.

Keep the boarding pass, the original ticket, and every receipt from the disruption onward: food, drink, transport, and accommodation. If the airline does not arrange care directly, you can buy reasonable replacement care yourself and claim it back; receipts are required and the amounts must be reasonable. Submit the formal claim in writing after the trip rather than at the desk; airlines pay out faster on a written claim with receipts attached than on a verbal request in the middle of disruption.

If the airline refuses a legitimate claim, the CAA's complaint process is free. Aviation Alternative Dispute Resolution schemes (AviationADR and CEDR) handle binding decisions at no cost to the consumer, usually within three months. Claim-management companies that take a percentage of the payout are rarely worth using when the airline's own process and the ADR route are both free. Your rights when a flight is cancelled walks through the full claim process and the escalation paths if the first claim is refused.