The ticket price became an entry point
When airlines separated checked baggage from the ticket, they changed what the fare represents. The advertised price could cover the seat and basic transport, while services some passengers do not use—or value equally—could be priced separately. That makes the initial fare look lower and gives travelers more control over what they buy.
It also helps airlines compete in a market where many customers compare prices before choosing a flight. A lower headline fare can attract attention; baggage charges collect additional revenue from passengers who need the service. The bag has become an optional purchase attached to the trip, rather than a cost folded into every ticket.
One fee serves different travelers
A passenger traveling light may be willing to accept a cheaper ticket without a checked bag. Someone carrying several bags may be willing to pay more for the same seat. Separating the charge lets airlines capture some of that difference in willingness to pay—without requiring every passenger to buy the same bundle.
Fees can also vary with the number of bags or the conditions of the ticket. Those distinctions give passengers a reason to plan ahead and let airlines charge more when a traveler has fewer alternatives, such as at the airport. The tradeoff is less certainty: a fare that looks inexpensive at first can cost more once necessary extras are added.
Revenue is not the same as profit
Baggage fees bring in substantial revenue, but handling bags still costs money: they must be tagged, moved, loaded, and delivered. The business appeal is that airlines can charge directly for a service while keeping it out of the base fare for travelers who do not use it. A bag fee is therefore not simply a bonus payment; it is a way to divide the price of a trip into smaller, more targeted charges.
