The research, carried out by refund.me, suggests that any flight outbound from the EU, regardless of destination, is covered by EU 261/04 and thus eligible for compensation if delayed by three or more hours.

For example, TAP Portugal flight TP77 from Lisbon to Rio de Janeiro on June 27 was delayed by almost eight hours. Every passenger on that flight has the right to claim £475 (€600).

In the decade since EU 261 was passed into law, refund.me estimates more than £3.2 billion has been unclaimed, as only 2% of eligible passengers successfully claim.

“Too many people do not know about their right to compensation. Those who try to claim individually find it very difficult. We aim to make that process more transparent and attainable,” said Eve Buechner, Founder and CEO of refund.me.

In two separate cases last month, the UK Court of Appeal ruled that passengers can claim compensation as far back as six years, and that mechanical faults on routine check-ups did not exempt the airline.

However, flyers are claiming more compensation as awareness of passenger rights rises and some airlines improve their service. Last year, refund.me estimated £250 million was unclaimed.

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