The last set of accounts for the airport operator shows a turnover for the 13m passengers reached over £227m with an operating profit of £64m for its foreign owners. This is why everything is so expensive at Luton and in fact at all major airports, as they fleece captive passengers by taking a major cut of the income these eateries generate, which in turn means high prices for even a bottle of water.
How much are those passengers paying to fly, and consequently how much are the airlines paying the airports? It's not fleecing, it's just a different way of funding airports.