Under long-standing U.S. DOT rules, you have 24 hours from the time of booking to cancel a flight for a full refund, provided the flight was booked at least seven days before departure. However, in 2026, there is a major update for international travelers: as of February 24, 2026, the DGCA in India has implemented a new 48-hour "Look-in option." This allows passengers to cancel or amend a ticket for free within 48 hours of booking, provided the flight is at least 7 days (domestic) or 15 days (international) away. For most other global airlines, if you miss the initial 24-hour window, you can still cancel, but you will likely receive a Flight Credit rather than a cash refund, unless you purchased a "Flexible" or "Refundable" fare. A "pro-tip" for 2026 is to always book directly through the airline's website to ensure these "look-in" and "24-hour" rules are applied without the extra fees often charged by third-party agents.