What is the EU compensation regulation EU261 for cancelled flights?

The Flight Compensation Regulation 2004 (EC) No 261/2004 is a regulation in EU law establishing common rules on compensation and assistance to passengers in the event of denied boarding, flight cancellations, or long delays of flights. It requires compensation of €250 to €600 depending on the flight distance for delays over of at least three hours, cancellations, or being denied boarding from overbooking. Delays shorter than three hours means no entitlement to any compensation of any kind even if the delay was classified as non-extraordinary. Airlines must provide refreshments and accommodation where appropriate. The Court of Justice of the European Union has interpreted passenger rights strictly, so that there are virtually no exceptions for airlines to evade their obligations for breach of contract. It repealed Regulation (EEC) No 295/91, and went into effect on 17 February 2005.

The EU in 2004, passed regulation EU 261 to protect passengers against severe flight disruptions such as long delays, cancellations, missed connections and flight re-bookings. The exact compensation amount is dependent on the flight distance and delays of over 3 hours, cancellations, or being denied boarding due to overbooking. The regulation went into effect as of February 2005.