It just so happens that I know this answer.

Airports charge a passenger fee. It is a Federal "fee" on passengers, that pays for FAA approved expenditures, including aviation related improvements to facilities. Parking is another cash cow, concessions, et cetera make up most of this. Distance based fees have been discussed as potential greenhouse fees, but I'm not sure where we are with that in the US.

The "Passenger Fare Charge" or PFC is charged through your ticket, as an enplainging passenger. Charges vary with LAX being the highest and Bob Hope being one of the lowest in the LA region. The difference in the ancient age of BHA and the size of facilities explains much of this. LAX has high volumes, expensive facilities, and high costs.

The high cost basis differentical charged at Ontario, which is run by LAX, is the basis for the locals wanting to take control of that facility away from the CLA. Ontario was growing rapidly in the 90's and for a while after 9/11, then from 06 to now passenger numbers have tanked, and flights have been cut significantly, resulting in high fixed costs, spread against low volumes.

A "glut" of underutlized excess marginal airspace and terminal capacity in the Bay Area and Sou Cal is just another reason the current costly "Super" HSR design is unwarranted, and fails to meet real inter-urban middle distance HSR needs, with an affordable somewhat "slower" HSR option, which would actually help relieve this weekends highway congestion.