In 2026, it is generally not cheaper to wait until you are at the airport to upgrade to Business Class. Most airlines now use high-value "dynamic pricing" and automated "upgrade bidding" systems to fill their premium cabins days before the flight. Upgrading online or via the app 48–72 hours before departure is typically the premier way to find the lowest "discounted" upgrade rates. By the time you reach the airport check-in counter, the airline knows exactly how many seats are left and may charge a "last-minute" premium or have no inventory at all. The only high-value exception is the "Upfront Upgrade" occasionally offered at the gate if the flight is overbooked in Economy; however, these are rare and unpredictable. For the best value, monitor your email for "exclusive upgrade offers" in the week leading up to your trip, as these represent the airline's effort to secure a guaranteed sale before the "day-of" standby lists take over at the terminal.