If economy seats are full and business class seats are not, you have a much better chance at scoring a cheap, last-minute upgrade. To evaluate your chances of an upgrade, check your flight 24 hours before departure to find out how full it is.

Upgrading to Business Class last minute can often be significantly cheaper than booking the seat outright, but it is a "high-stakes gamble" that depends on the airline's remaining inventory. Many airlines in 2026 use "Bid-for-Upgrade" systems (like Plusgrade), where you can name your price 48 to 72 hours before departure. If the cabin is not full, they may accept bids as low as $300 to $600 for a long-haul flight. Another "pro-tip" is to check the airline’s mobile app during the 24-hour check-in window; airlines often offer "Fire Sale" upgrades at this stage to monetize every available seat. However, if the flight is nearly full or a high-level elite member is on the waitlist, the "last minute" price may actually skyrocket or disappear entirely. It is generally cheaper to upgrade "at the kiosk" or "at the gate" only if the airline is desperate to fill the cabin, but for popular routes, the most reliable and often most "value-optimized" upgrades are those secured via points or bidding several days in advance.