Airline baggage fees are charges that airlines impose for checking in luggage or carrying extra bags on flights. These fees can vary widely depending on the airline, the route, and the type of ticket purchased. Many airlines allow one free carry-on bag, but additional bags or overweight luggage often come with extra costs. Travelers should be aware of these fees when booking flights, as they can significantly increase the overall price of a trip. To avoid surprises, it's a good idea to check the specific baggage policies of the chosen airline, such as Delta, American Airlines, or Southwest.