Many airlines, especially low-cost carriers such as Ireland's Ryanair, make a vast proportion of their revenue from ancillary fees. With this in mind, we thought we’d take a closer look at ancillary fees and see if they are worth buying.

While one might expect that buying a seat on the plane is the way airlines make their money, ancillary fees or add ons account for a vast percentage of many airline's revenues. Traditional national flag carriers like British Airways and Iberia make extra revenue by selling premium products like first and business class seats. They also charge for internet use and have onboard duty-free shopping.

Low-cost carriers and no-frills airlines take a different approach by sometimes offering hard-to-believe ticket prices and then charging passengers for everything else.

Full-service carriers ancillary fees

Using British Airways as an example of what full-service airlines charge extra for, most aspects, including food and drinks, are considered part of your ticket price. However, saying that there are a few extras they charge for, as can be seen in the list below:

• Ticket changes: If you need to change your ticket, cancel your flight or buy new tickets, you may be charged a service fee.
• Luggage: British Airways baggage allowance depends on which class of service you are flying. If you are flying in economy and have extra luggage, you will be charged $90 for an additional suitcase.
• Overweight luggage: If your baggage exceeds the permitted weight allowed, you will pay a fee of $100.
• Internet: British Airways charges $8 for one hour, $18 for four hours, and $24 for the entire flight.

Full-service carriers also make ancillary revenue from banks and merchants that buy miles in the carrier's frequent flyer programs. Overall, it is estimated that 55% of full-service carrier's ancillary revenues comes from the sale of frequent flyer points to their marketing partners.

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Low-cost carriers ancillary fees

No airline makes more money on ancillary fees than Ryanair, which has turned selling add ons as a way of being able to offer some of the cheapest tickets you will find anywhere. Ryanair has a business model which it copied from Southwest Airlines and then perfected. After having paid for the ticket.

We have listed below a list of Ryanair ancillary add ons:

• Seat selection: All Ryanair planes are configured in an all-economy layout, with seat prices ranging from $8 to $33. 
• Luggage: If you have more baggage than a small carry-on, you can expect to pay $19.10. Musical instruments, sports equipment, and baby strollers are charged $19.
• Priority boarding: You can pay $7.16 to board the aircraft first.
• Food & Drink: Ryanair charges for all food and drinks and has pre-ordered snacks available from $11.
• Travel insurance: Ryanair sells travel insurance starting from $23.77.

Ryanair cabin crew work hard

Unlike many airlines where you may have to press a button to get a flight attendant's attention, this is never an issue on Ryanair as the cabin crew is constantly up and down the aisle trying to sell you everything from mobile recharging devices to scratch-off lottery tickets. However, having said that, they never try and force you into buying anything.

What do you think about airline ancillary fees? Please tell us what you think in the comments.