Yes, at least in Europe. Ryanair is infamous for pushing a very hard bargain with airports, but it's common with all the low-cost airlines.

Part of the airport's willingness to give Ryanair a discount is the expectation of full planes with a lot of seats, so there are more people to sell to.

e.g. [1] Table 6, Warsaw Modlin airport charges Ryanair 6 PLN (€1.30) per passenger, vs the normal 40 PLN (€8.50). That's obviously significant when they sell flights for €15 or so.

[1] https://www.researchgate.net/publication/317710545_Internati...