Glossary · Travel distribution
Ancillary revenue
Ancillary revenue is the income an airline or other travel supplier earns beyond the base fare or room rate — checked bags, seat selection, priority boarding, meals, change fees, and commission on hotels, car hire or insurance sold alongside the trip.
Reviewed 30 Oct 2026
What counts as ancillary
| Kind | Examples |
|---|---|
| À la carte services | Checked or cabin bags, seat selection, priority boarding, onboard food, extra legroom |
| Fare bundles | Branded fares that package a bag, seat and flexibility at one price |
| Flexibility | Change and cancellation fees, or the price difference to a flexible fare |
| Partner commission | Hotels, car hire, transfers and travel insurance sold through the airline's site |
Why it changes what a fare means
Once bags and seats are priced separately, the cheapest base fare is not necessarily the cheapest trip. Two carriers can show the same headline price for a route and differ widely once a checked bag is added. The pattern is strongest at low-cost carriers, but most network airlines now sell branded fares with different inclusions as well.
NDC lets airlines put those bundles and extras into the offers they send to sellers, so ancillary prices increasingly appear outside the airline's own website too.
EU rules on optional extras
For air services covered by Regulation (EC) No 1008/2008, Article 23(1) requires the final price to include all unavoidable and foreseeable taxes, charges, surcharges and fees, and requires optional price supplements to be communicated clearly at the start of the booking process and accepted on an opt-in basis. Extras the passenger chooses are therefore shown separately; charges nobody can avoid are not supposed to be. This describes the text, not its application to a given airline.
Collecting ancillary prices
Record the base fare, the fare brand and what it includes, then the price of each extra for the same flight and date, all from one point of sale. The setup is on airline ancillary prices, and the carrier-specific detail on low-cost carrier fares.
FAQ
Questions
Something not covered? Write to contact@arcproxies.io.
Why are bag fees not included in the fare?
Because many airlines unbundle them: the base fare covers the seat, and a checked bag is an optional service. In the EU, optional supplements must be shown clearly at the start of booking and chosen by the passenger, rather than added by default.
Is a seat selection fee ancillary revenue?
Yes. Paid seat selection is one of the most common ancillaries, alongside bags, priority boarding and change fees.
Are pre-ticked extras allowed on EU flight bookings?
Article 23(1) of Regulation 1008/2008 says acceptance of optional price supplements must be on an opt-in basis, which is generally read as ruling out pre-selected extras. Whether a specific booking flow complies is a question for counsel.
How do I compare fares that include different extras?
Normalise to a fixed trip: for example, one cabin bag and one checked bag, no seat selection. Add each carrier's price for those extras to its base fare, using prices collected at the same time from the same market.
Sources & review
Last reviewed by the ARC Proxies team. Prices are read from the live catalog at build time.
In practice