12 Flight Cancellation Refund Rules Every Passenger Should Know (2025 Update)

2. What counts as a "significant change"

Rule summary: The DOT’s rule defines “significant change” thresholds that trigger refund rights. For domestic flights the common threshold is three hours or more of delay in arrival; for international flights the benchmark is six hours or more. Significant changes also include airport swaps, added connections, or downgrades in service class. These thresholds give passengers clearer grounds to request refunds when the airline’s new schedule makes the trip impractical. How to measure: start from your original scheduled arrival time and compare to the newly proposed arrival. If the difference meets or exceeds the three- or six-hour threshold, the change qualifies. Keep screenshots of your original itinerary and the revised itinerary showing times and airports. If the airline moves you to a different airport that increases travel time or adds costly transfers, treat that as a significant change and ask for a refund. Action tip: when staff or the app offers alternate flights, ask explicitly whether the change meets DOT’s definition and whether a cash refund is available. If the agent seems unsure, capture their name and the time of the conversation. That will help if you need to escalate or file a DOT complaint.