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Plain-English deep dives on flight operations, emissions science, sustainable aviation fuel, jet-lag chronobiology, and the airports and routes that anchor global aviation.

Ten plain-English deep dives on the bits of aviation operations, emissions science, and travel chronobiology that the calculator touches but does not explain in detail. Each page cites primary sources directly. The methodology pages live at /methodology — these are the applied companions.
10
Topic pages across Aviation, Emissions, and Travel
This index
5+
Primary sources cited on every topic page
Per Sources block
100%
Free to read, no signup required
By design
0
First-party trackers by AirMilesCalc itself; AdSense funding is planned post-approval — see /privacy
By policy
Primary sources · 6
  1. [1] Lee et al. (2021) — Aviation effective radiative forcing decomposition — anchors the radiative-forcing and cabin-class pages · Atmospheric Environment 244, 117834 · January 2021 https://doi.org/10.1016/j.atmosenv.2020.117834
  2. [2] DESNZ 2024 GHG conversion factors — UK government per-passenger-km CO₂e factors — anchors the emissions cluster · UK gov.uk · June 2024 https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2024
  3. [3] Sack (2010) NEJM jet-lag review — Anchors the jet-lag chronobiology page — phase-delay vs phase-advance asymmetry · New England Journal of Medicine 362:440-447 · February 2010 https://www.nejm.org/doi/full/10.1056/NEJMcp0909838
  4. [4] ACI World — Top 20 busiest airports — Annual passenger-traffic ranking — anchors the busiest-airports page · Airports Council International · July 2024 (for 2023 data) https://aci.aero/2024/07/16/top-20-busiest-airports-in-the-world-confirmed-by-aci-world/
  5. [5] IATA Fly Net Zero 2050 — Industry net-zero pathway resolution — anchors the SAF and CORSIA pages · IATA AGM 77, Boston · 4 October 2021 https://www.iata.org/en/programs/sustainability/flynetzero/
  6. [6] ICAO CORSIA programme — International aviation carbon offsetting scheme — anchors the CORSIA page · International Civil Aviation Organization · Phases 2021–2035 https://www.icao.int/environmental-protection/CORSIA/Pages/default.aspx

How these pages relate to the calculator

The calculator on the homepage returns six numbers per route — distance, block time, per-cabin CO₂e, bearing, cruising altitude, and jet-lag recovery. Each of those numbers has a story behind it. The Aviation pages explain the operating context that shapes block time, altitude, and route choice; the Emissions pages explain the DEFRA cabin multipliers and the 1.9 × radiative-forcing uplift that turn distance into CO₂e; the Travel page covers the chronobiology that determines whether the jet-lag estimate is mild or severe.

The full formal methodology — Vincenty's formula, the WGS-84 ellipsoid parameters, DESNZ's 2024 conversion factors, Lee et al.'s 2021 radiative-forcing decomposition — lives at /methodology. The /learn pages below are the plain-English companions, written so a non-specialist reader can verify the numbers without first mastering the underlying math.

Reading paths by audience

The ten pages do not need to be read in order. Most readers arrive with a specific question and leave once it is answered. The four paths below sequence the pages so each new page builds on the one before it, depending on what you came to find out.

For frequent flyers
Start at jet-lag science to recalibrate your travel routine, then cabin-class CO₂ to anchor what your annual mileage actually costs the atmosphere, and finish at airline alliances to understand which partner offers reciprocal mileage on your next leg.
For sustainability and ESG teams
Start at cabin-class CO₂ for the per-ticket arithmetic, then SAF for the supply-side picture, and CORSIA for the international regulatory layer that becomes mandatory in 2027. Pair with DEFRA factors.
For aviation enthusiasts
Start at longest flights for the route topology, then cruise speeds and cruising altitude for the operating envelope, and busiest airports for the network topology these flights move through.
For educators and students
Start at nautical miles for the unit history, branch to great-circle distance for the geometry, and finish at jet-lag chronobiology for the biological-systems angle on travel.

Calculator output → background page mapping

Every figure the calculator shows on a results page has a /learn companion that explains what it represents and where the assumptions live. The mapping below is the canonical pairing — use it when you want to verify a specific number rather than read the full theory.

Calculator output/learn companionWhat it explains
Distance (km / mi / NM)nautical-milesWhy aviation reports distance in nautical miles and how the unit relates to the metre and the statute mile.
Block timeaircraft-cruise-speeds + cruising-altitudeWhy 850 km/h is the right single-number reference for narrow- and wide-body cruise.
CO₂e per cabincabin-class-emissionsWhy business class is allocated ≈ 2.9 × economy on the same flight (it is a floor-area-allocation choice, not a fuel-burn measurement).
Jet-lag recovery daysjet-lag-scienceWhy westward recovery runs at 92 minutes per day and eastward at 57 — the human circadian period averages 24.2 hours.
Route classification (ULR / long-haul / ...)longest-flights-in-the-worldWhat aircraft can fly ultra-long-range routes non-stop and how they trade payload for fuel.
Airline list per routeairline-alliancesWhich alliance dominates which corridor and how status reciprocity works.
Origin / destination hubbusiest-airports-in-the-worldWhere the route fits in the global passenger-traffic ranking and what the hub geography looks like.
CO₂ offset estimate (trees)corsia + sustainable-aviation-fuelWhat an airline-level carbon credit actually buys and why SAF is the harder-but-more-permanent abatement path.

Aviation

How aircraft actually operate the routes the calculator measures. Cruise speeds and altitudes that anchor the 850 km/h flight-time reference; the world's longest scheduled non-stops and the ultra-long-range aircraft that fly them; the busiest airports by passenger traffic; and the alliance structure that coordinates international long-haul scheduling.

The nautical mile — exactly 1,852 metres →
Why aviation and maritime navigation still use nautical miles, where 1,852 m came from, and why the unit survives.
Aircraft cruise speeds, by type →
Cruise speeds for the dozen aircraft types that fly most commercial passengers — Mach number, km/h.
Why aircraft cruise at 35,000 feet →
Most commercial flights cruise between FL350 and FL410, the result of a tight drag-fuel-ceiling trade.
The world's longest commercial flights →
SQ23 Singapore–JFK leads at 15,349 km and 18 h 40 min — here is the current top ten.
The world's busiest airports →
Atlanta at 104.6 million passengers in 2023 — ACI World's ranked top ten with passenger numbers.
Airline alliances — Star, oneworld, SkyTeam →
The three global alliances, their 25 / 13 / 19 member airlines, and what alliance status actually gets you.

Emissions

Where the per-passenger CO₂ numbers come from, why business class is allocated roughly 2.9 × economy on the same flight, and how the industry plans to bridge the gap from 0.3 % SAF in 2024 to a net-zero pathway by 2050 — including the CORSIA market-based measure that becomes mandatory in 2027.

Cabin class and your CO₂ footprint →
Business class emits roughly 2.9 × economy on the same flight — the math and the rationale.
CORSIA, explained →
ICAO's global aviation carbon scheme enters mandatory phase in 2027 — here is what it actually requires.
Sustainable aviation fuel — where the industry actually is →
SAF is 0.3 % of global jet fuel in 2024; the IATA pathway needs 65 % by 2050. The gap is the story.

Travel

Applied chronobiology — why westward jet-lag recovery runs at about 92 minutes per day while eastward only manages 57, the asymmetry that determines whether a 9-hour shift takes 6 days or 9.5 days to fully reset.

Jet lag, eastbound vs westbound →
Why westward recovery runs at ~92 min/day and eastward at ~57 min/day — circadian period plus light.

Frequently asked

How are these pages different from /methodology?▾
The /methodology pages are formal technical references — they describe the exact formulas, constants, and primary sources behind every number the calculator returns. The /learn pages are applied companions, written so a non-specialist reader can understand the implications without first mastering the math.
Are the numbers on these pages up to date?▾
Each /learn page is dated at the top with the last verification date. Numbers are pulled from primary sources — DESNZ for emissions factors, ACI World for airport rankings, IATA for fleet stats, Singapore Airlines schedules for ULR routes — and we update annually or when a published source ships a material revision.
Can I cite these pages in academic work?▾
Yes, but prefer to cite the underlying primary sources (listed in each page's Sources block) rather than the AirMilesCalc page itself. This keeps your citation trail clean and lets reviewers verify directly against the regulator or peer-reviewed paper.
Why is there no page about [some other aviation topic]?▾
The /learn cluster covers topics the calculator surfaces directly — distance, time, CO₂, jet lag, cabin class, longest flights, busiest airports, alliances, CORSIA, SAF. Topics outside the calculator's scope (booking systems, frequent-flyer programs, in-flight service) are deliberately left to specialist sites that focus on them.
Do the /learn pages have schema.org markup?▾
Yes — every subpage emits TechArticle, BreadcrumbList, and FAQPage JSON-LD, and is canonical-linked. Sources blocks expose primary citations directly in the page body so AI assistants and search crawlers find them without needing to follow links.