Data methodology

How airline fee records are sourced and verified

We turn fragmented official airline policies into qualified records and deterministic tools. We preserve uncertainty when an airline does not publish one universal answer.

Latest verification date present in the database: 2026-09-28

What every published fee record must contain

A number without scope is not enough. Each public fee record must identify the amount or published limitation, currency, who it applies to, route or market, purchase timing, conditions, official source URL, and date checked.

The fact

Amount or allowance, currency, bag or service type, and relevant threshold.

The scope

Fare, cabin, route, traveler type, timing, and other qualifications that change the answer.

The evidence

Official source link and record-level last-verified date.

Source hierarchy

Official airline publications come first

Third-party sites may reveal that a policy deserves another look, but they do not become authoritative inputs to the fee database. A material claim should trace back to the airline that publishes or applies the rule.

  1. 1
    Airline fee or policy page
    Preferred when the airline publishes the rule directly for travelers.
  2. 2
    Airline conditions or tariff
    Used when formal terms provide qualifications missing from the summary page.
  3. 3
    Airline booking flow or calculator
    Used for itinerary-priced products when a universal amount is not published.
  4. 4
    Airline help center
    Used for official explanations, exceptions, and traveler eligibility.
  5. 5
    Other official airline publication
    Used only when it directly supports the stated fact.

Published rule versus derived answer

Stored fact

The airline publishes a fee, allowance, threshold, or limitation with route, fare, and timing qualifications.

Deterministic result

A calculator applies explicit traveler inputs to usable records. It does not guess a price when the airline requires an itinerary lookup.

Labels such as route lookup needed, price shown during booking, or not published are intentional. They are more accurate than presenting a representative amount as though it applied universally.

Verification freshness

A last-checked date records when the cited official source was reviewed. It is not a guarantee that the airline has made no later change. Public freshness labels currently follow these deterministic thresholds:

Recently checked
Official source checked within 120 days.
Review due
More than 120 but no more than 240 days old.
Needs recheck
More than 240 days old; confirm before relying on time-sensitive pricing.

Change detection and publication

STEP 1
Monitor
STEP 2
Detect
STEP 3
Inspect
STEP 4
Verify
STEP 5
Publish

Automation can detect source changes and prepare a review item. It cannot mark a material claim verified. The claim-level provenance validator requires human review before a revision can receive verified status.

Current coverage boundary

Claim-level history is still a controlled pilot

All fee rows carry official source links and record-level verification dates. The deeper system—with individual claim IDs, evidence paths, revisions, effective-date status, review cadence, and retained history—is currently implemented for Air France baggage policy. It has not yet been represented as universal coverage.

View the Air France implementationBrowse fee recordsSee deterministic trip math

What verification does not mean

  • It does not guarantee availability or price for a future itinerary.
  • It does not override the operating carrier, ticket, airport agent, or airline checkout.
  • It does not convert a route-priced product into a universal fee.
  • It does not treat a newer page-level date as proof that every older record was rechecked.