Measure the delay at the final destination
Care thresholds generally begin after two hours for short flights, three hours for medium distances and four hours for long-haul journeys. Under UK guidance, a delay of five hours can also create a choice not to travel and seek a refund for unused travel.
Check the compensation band
Current EU261 commonly uses a three-hour final-arrival threshold, subject to coverage and extraordinary circumstances. Standard EU bands are €250, €400 and €600. UK261 uses £220, £350, £260 or £520 depending on distance and long-haul arrival delay.
Test the extraordinary-circumstances response
An airline relying on extraordinary circumstances should identify the external event and the reasonable measures taken. A generic phrase is not the same as evidence about the specific flight.
Documents to prepare
Before sending the request
State the remedy clearly. Fixed compensation, reasonable expenses, reimbursement and rerouting are separate requests even when they arise from the same disruption.