Since 2024, US rules require automatic cash refunds when a flight is cancelled or significantly changed and you don't travel. What counts, how fast you are paid, and what US law doesn't give you.
Since Brexit the UK has its own copy of EU261, paid in pounds. Which flights it covers, the £220–£520 amounts, how ADR and the CAA fit in, and where it overlaps with EU rules.
Regulation 261/2004 can pay €250–€600 when a flight is cancelled, badly delayed or overbooked. Who it covers, what you are owed, when airlines can refuse, and how to claim.