Seven document families,
one shared structure.
AFID reads each airport's own primary documents and turns them into figures you can line up against each other. Here is what the corpus holds and where each number comes from.
Rates & charges
From each airport's published rate schedule or resolution.
Signatory and nonsignatory landing fees, terminal rents by space type, and itemized fee lines, normalized into one taxonomy so a fee at one airport lines up with the same fee at another. Where a rate is set inside the airline use & lease agreement rather than a published schedule, AFID says so instead of leaving a blank that looks like zero.
Audited financials
From the ACFR, CAFR, or adopted budget.
Revenue composition, cost per enplanement, operating results, debt outstanding, days cash on hand, and debt service coverage, each tagged with its fiscal year and its reporting scope. When an airport reports inside a larger city or authority statement, that scope is recorded on the figure so you never mistake a combined number for a standalone one.
Agreements & debt
From executed use & lease agreements and bond official statements.
Rate-setting methodology, agreement term, revenue sharing, and the key disclosures from the bond official statement. This is the layer that makes comparison honest: knowing whether an airport prices on a residual or compensatory basis is what tells AFID which figures can sit in the same ranking and which can only sit as context.
Incentives & capital plans
From incentive program documents and capital or master plans.
Air carrier incentive programs and capital or master plans where the airport has published them. Coverage of these families grows as documents are located and verified; until then, the field is shown as not yet published rather than estimated.
Coverage
Defined by the FAA, not by who subscribes.
AFID's airport list follows the FAA's commercial-service definition, and coverage expands as documents are gathered and checked. Every figure that is missing is missing on purpose, with a stated reason, because a disclosed gap is worth more to an analyst than a confident guess. You always know what AFID has, what it does not, and why.