Yes, you can pay for checked baggage at the airport, but in 2026, it is almost always the most expensive option. Most airlines, including JetBlue, American, and United, charge a "premium" for bags paid at the check-in counter or kiosk, often $5 to $10 more per bag than if you had paid during online check-in or via the airline's app. For example, a first bag that costs $35 online might cost $40 to $45 at the airport. Furthermore, if you arrive at the boarding gate with a bag that exceeds the carry-on limit, you will be forced to "gate-check" it, which often incurs a much higher flat fee (sometimes $65 or more). To save money and time, savvy travelers use their airline’s mobile app to add and pay for bags up to 24 hours before departure, allowing them to use the faster "Bag Drop" lanes instead of waiting in the full-service check-in queue.