# AirMilesCalc

> Free, ad-supported geodesic flight-distance and emissions calculator. Uses
> Vincenty's 1975 inverse formula on the WGS-84 ellipsoid for sub-millimetre
> distance precision; DESNZ 2024 conversion factors for CO₂ with the 1.9 ×
> radiative-forcing uplift; OpenFlights for airport / airline / route reference
> data; Sack 2010 chronobiology for jet-lag estimates.

This file follows the llms.txt convention so language-model agents can find the
canonical resources without crawling JavaScript-heavy template pages.

## Calculator and APIs

- [Distance calculator](https://airmilescalc.com/): main entry; computes distance,
  block time, per-cabin CO₂e, bearing, and jet-lag for any pair of airports.
- [POST /api/calculate](https://airmilescalc.com/api/calculate): JSON endpoint
  accepting `{ fromIata, toIata, cabinClass? }` and returning the full result.
- [GET /api/airports/search?q=…](https://airmilescalc.com/api/airports/search):
  IATA / city / name autocomplete.

## Methodology (primary sources cited per page)

- [Methodology umbrella](https://airmilescalc.com/methodology): every formula
  and constant the calculator uses, with sources.
- [Vincenty's formula](https://airmilescalc.com/methodology/vincenty-formula):
  iterative algorithm, convergence behaviour, antipodal edge case.
- [Haversine formula](https://airmilescalc.com/methodology/haversine-formula):
  the spherical fallback used for near-antipodal pairs.
- [Great-circle distance](https://airmilescalc.com/methodology/great-circle-distance):
  geometric intuition for the shortest path on a sphere.
- [WGS-84 ellipsoid](https://airmilescalc.com/methodology/wgs84-ellipsoid):
  defining parameters (a, 1/f, GM, ω) per NGA.STND.0036.
- [Rhumb line vs great circle](https://airmilescalc.com/methodology/rhumb-line):
  loxodromes and Mercator projection.
- [End-to-end CO₂ calculation](https://airmilescalc.com/methodology/co2-emissions-calculation):
  pipeline from distance to per-cabin kg CO₂e.
- [DEFRA / DESNZ 2024 emission factors](https://airmilescalc.com/methodology/defra-emission-factors):
  UK Government per-passenger-km factors for three distance bands.
- [Aviation radiative forcing](https://airmilescalc.com/methodology/radiative-forcing):
  Lee et al. 2021 ERF decomposition and the 1.9 × CO₂ → CO₂e uplift.
- [Flight-time estimation](https://airmilescalc.com/methodology/flight-time-calculation):
  850 km/h cruise reference plus banded ground time.

## Applied / educational

- [Learn umbrella](https://airmilescalc.com/learn): index of applied content.
- [Nautical miles](https://airmilescalc.com/learn/nautical-miles): 1,852 m exactly,
  fixed at Monaco 1929.
- [Aircraft cruise speeds](https://airmilescalc.com/learn/aircraft-cruise-speeds):
  Mach 0.78 narrow-body, Mach 0.85 wide-body.
- [Cruising altitude](https://airmilescalc.com/learn/cruising-altitude): FL350–FL410
  fuel-efficiency band.
- [Cabin class and CO₂](https://airmilescalc.com/learn/cabin-class-emissions):
  business ≈ 2.9 × economy on the same flight.
- [Jet lag science](https://airmilescalc.com/learn/jet-lag-science): east vs west
  asymmetry, 92 vs 57 minutes per day recovery.
- [CORSIA, explained](https://airmilescalc.com/learn/corsia): ICAO's market-based
  measure entering mandatory phase 2027.
- [Sustainable aviation fuel](https://airmilescalc.com/learn/sustainable-aviation-fuel):
  0.3 % of jet fuel in 2024, IATA target 65 % by 2050.
- [Longest flights](https://airmilescalc.com/learn/longest-flights-in-the-world):
  SQ23 Singapore → JFK at 15,349 km.
- [Busiest airports](https://airmilescalc.com/learn/busiest-airports-in-the-world):
  ACI World 2023 — ATL at 104.6 M passengers.
- [Airline alliances](https://airmilescalc.com/learn/airline-alliances):
  Star (25), oneworld (13), SkyTeam (19).

## Project and policy

- [About AirMilesCalc](https://airmilescalc.com/about): mission, audience, who
  runs the site, limitations.
- [Privacy policy](https://airmilescalc.com/privacy): first-party data position,
  Google AdSense disclosure, cookie inventory, GDPR / CCPA / LGPD / PIPEDA / UK GDPR.
- [Terms of service](https://airmilescalc.com/terms): usage rights, disclaimers.
- [Contact](https://airmilescalc.com/contact): editorial corrections, partnerships.
- [Accessibility](https://airmilescalc.com/accessibility): WCAG 2.1 AA goal,
  known limitations, EAA compliance tracking.

## Reference data sources

- OpenFlights (ODbL): https://openflights.org/data.php — airports, airlines,
  routes (routes snapshot June 2014).
- DESNZ 2024 conversion factors: https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2024
- Vincenty 1975 paper (NGS hosting): https://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
- NGA WGS-84 standard: https://earth-info.nga.mil/index.php?dir=wgs84&action=wgs84
- Lee et al. 2021 aviation ERF: https://doi.org/10.1016/j.atmosenv.2020.117834
- ICAO CORSIA: https://www.icao.int/environmental-protection/CORSIA/Pages/default.aspx
- IATA Fly Net Zero 2050: https://www.iata.org/en/programs/sustainability/flynetzero/

## Optional

- [Sitemap](https://airmilescalc.com/sitemap.xml): full URL index including
  thousands of route, airport, and country pages.
- [Robots](https://airmilescalc.com/robots.txt): /api/ is disallowed for general
  crawlers; everything else is indexable.