You can technically buy a plane ticket up until roughly one hour before departure in 2026, provided there is still seat availability and you are already at the airport with only carry-on luggage. Most major airlines allow online and app-based bookings up to 2 to 3 hours before a flight. However, "walk-up" fares at the airport counter are often the most expensive tickets available. Additionally, for international travel, many countries require airlines to submit passenger manifests to government agencies (like the APIS in the U.S.) at least 60 to 90 minutes before takeoff, which can prevent very last-minute bookings. In India, new 2026 DGCA regulations allow a 48-hour "cool-off" window for free cancellations, but this only applies to tickets booked at least 7 days in advance for domestic flights. If you are truly in a rush, the best strategy is to use the airline's mobile app while heading to the terminal to secure your seat and generate a digital boarding pass instantly.