It is a regulation established by the European Union to protect the rights of air passengers and ensure fair compensation and assistance in case of flight disruptions. The regulation applies to all flights departing from airports located in the EU and flights operated by EU-based airlines arriving in the EU from non-EU countries.

EU261 covers the following key areas:

1. Flight Cancellations: If your flight is cancelled, the airline must offer you the choice between a full refund of the ticket or re-routing to your final destination at the earliest opportunity, under comparable transport conditions.

2. Flight Delays: In case of a significant delay (usually more than 3 hours, depending on the distance of the flight), the airline must provide assistance, such as meals, refreshments, and communication facilities.

3. Denied Boarding (Overbooking): If you are denied boarding due to overbooking, you may be entitled to compensation, depending on the length of the delay you experience at your final destination.

4. Connecting Flights: EU261 covers connecting flights, so if you have booked a single journey with multiple flights and experience a delay, cancellation, or denied boarding on any leg of the journey, the regulation applies.

5. Extraordinary Circumstances: In some situations, airlines are exempt from paying compensation if the disruption was caused by circumstances beyond their control (e.g., severe weather, security threats, strikes, or air traffic management decisions).

6. Compensation: The compensation amount is determined based on the distance of the flight and the length of the delay. For example, for flights less than 1,500 kilometres, the compensation could be €250, while for flights between 1,500 and 3,500 kilometres, it could be €400. For longer flights (over 3,500 kilometres), the compensation could be up to €600.

7. Filing Claims: To claim compensation or request assistance, contact the airline directly.

It’s important to note that EU regulations may be updated or amended over time, so I recommend checking the latest official sources or consulting legal advice if you are seeking to understand the current state of EU261 regulations.