To claim compensation for a flight delay or cancellation in 2026, you should first visit the official website of the airline that operated your flight and search for their "Compensation" or "Passenger Rights" page. Most major carriers now provide a dedicated digital claim form where you enter your flight number and booking reference. Under EU Reg 261/2004 (or the UK equivalent), you are typically entitled to between £220 and £520 ($275–$650) if your flight arrived more than three hours late and the delay was within the airline's control (e.g., mechanical failure). You must provide receipts for any "duty of care" expenses, such as food or hotel stays, that the airline failed to provide. If the airline rejects your claim by citing "extraordinary circumstances" (like weather or air traffic control strikes), you can escalate the case to an Alternative Dispute Resolution (ADR) body or the Civil Aviation Authority (CAA). Avoid using "Claims Management Companies" initially, as they often take a 25–35% cut of your payout; claiming directly is free, and in 2026, most airlines are legally required to respond to your direct request within 60 days.