Baggage fees are extra charges that airlines impose for checking in luggage or bringing larger carry-on bags on flights. These fees can vary widely depending on the airline, the type of ticket purchased, and the weight or size of the bags. Travelers often need to pay these fees at the airport or when booking their tickets online, which can add to the overall cost of their trip. To avoid unexpected expenses, it's important for passengers to check the baggage policy of their chosen airline, such as Delta or American Airlines, before traveling. Some airlines offer free checked bags for certain ticket classes or frequent flyers, so knowing the rules can help save money.