Why may revenues related to passenger facility charges need to be estimated?

The need to estimate revenues related to passenger facility charges arises primarily because third-party remittances are involved. Passenger facility charges (PFCs) are fees collected by airlines on behalf of airports, and these fees can be subject to various collection and remittance processes. Since airlines may collect these fees from passengers at the time of ticket sales but remit them to the airports later, there is often a timing lag and uncertainty in the amount that will ultimately be remitted. This complexity necessitates estimation to account for potential discrepancies in collections and remittances, ensuring that airport financial planning and budgeting accurately reflect expected revenue from PFCs.

In contrast, fluctuating airport passenger numbers would lead to variations in revenue but wouldn't specifically necessitate estimation, as the charges are applied per passenger. While PFC amounts are regulated, the fixed nature of charges does not alleviate the need for estimation regarding how much revenue will actually be realized due to the involvement of third parties. Lastly, PFC revenues do not depend on airline profits, as they are independent of the airline's financial performance, further demonstrating why estimation is built around the complexities of third-party collection and remittance rather than the factors in the other options.