Flight Planning Tools Built Into
Great Circle Pro

Wind-Adjusted Aircraft Range Circles

Understanding what is reachable from any airport is one of the most fundamental questions in route planning, fleet deployment, and network strategy. Great Circle Pro's Range Circle tool renders geodetically accurate range rings around any airport in the database, giving you an immediate picture of which destinations fall within a given aircraft's maximum range.

Unlike flat-map range circles that distort severely with latitude, Great Circle Pro draws rings that correctly represent true great circle distance from the center point. This matters most at high-latitude hubs where Mercator distortion would make nearby destinations appear farther and distant polar-track cities appear closer than they are. The rings here reflect actual flight distances, not cartographic illusions.

Set the range in nautical miles or kilometers and place multiple concentric rings simultaneously to compare range variants of the same aircraft family or model different payload scenarios against range limits. Move the center point to any airport in the database and the rings replot instantly. Network planners use this to evaluate hub viability, spot thin markets just within reach, and compare fleet options without leaving the browser.

• Geodetically accurate rings - no Mercator latitude distortion
• Multiple concentric rings for variant and payload comparison
• Input in nautical miles or kilometers
• Instant replot when the center airport changes

Diversion Alternates You Can Actually Land On

Being inside the one engine inoperative diversion radius answers only half of the question. It tells you the aircraft can reach a field, not that it can land there. A diversion airport is genuine coverage only if it also has a suitable paved runway long enough for the specific aircraft you are flying. Great Circle Pro now runs that second check on every alternate, so a field that is in range but could never take your aircraft is no longer counted as coverage.

The map now separates in range from in range and landable, and every alternate shows its longest runway against the length your aircraft needs. A field that is close enough to reach but cannot land your aircraft, exactly the kind a check that looked only at range would have painted as good, is caught before it reaches a dispatch decision. That is ETOPS coverage you can trust at a glance, with no "in range but unlandable" surprises.

• Two independent tests on every alternate: inside one engine inoperative diversion range, and served by a runway your aircraft can actually use
• Requires a suitable paved runway long enough for the specific aircraft type selected
• Coverage states separate a reachable field from a reachable and landable one, so a too short runway is never mistaken for coverage
• Runway readout on every alternate, its longest runway against the length your aircraft needs, right on the map

Interactive Payload-Range Performance Chart

Payload-range charts define the performance envelope of an aircraft: the trade-off between how much revenue payload can be carried and how far it can be flown. Great Circle Pro's Payload-Range tab renders this chart interactively in the browser, letting planners and analysts plot the performance boundary of any aircraft type and overlay specific route distances against it.

The chart renders the three-segment payload-range curve that characterizes jet transport aircraft: the maximum structural payload segment where range is fuel-limited, the intermediate segment where payload trades for additional range, and the maximum fuel range segment where both payload and reserves sit at minimum. Each point on the curve reveals a dimension of operational flexibility, from belly freight capacity and full-load feasibility on long sectors to the outer limit of economic range extension.

Plot multiple aircraft types simultaneously to compare capabilities side by side and drop route distances directly onto the chart to see whether a mission falls in the unrestricted payload zone or into the trade-off region. Route strategists find this particularly useful when evaluating thin long-haul markets, assessing whether a longer-range variant is warranted, or quickly confirming whether a routing is physically feasible before deeper performance analysis.

• Three-segment curve with correct structural and fuel-limited breakpoints
• Multi-aircraft overlay for side-by-side type comparison
• Route distance plotted directly on the chart
• No software installation - runs entirely in the browser

Flight Emissions & CO2e Modal

Every Flight Plan card includes a Tier 2 Emissions Breakdown button that opens an interactive modal with the full carbon accounting picture for the selected route. Fuel burn is modelled per aircraft type across the climb, cruise, and descent phases of the flight, scaled by load factor; CO2 uses the standard 3.16 kg per kg of Jet-A stoichiometric ratio; CO2e applies Radiative Forcing Index 2.0 from Lee et al. 2021 to account for non-CO2 cruise-altitude warming effects (contrails, NOx, water vapour).

The modal breaks per-pax emissions down by cabin class: first, premium, business, and economy. It uses floor-area normalization. A first-class passenger correctly carries roughly 4× the per-pax footprint of an economy passenger on the same flight. A SAF blend slider models the lifecycle reduction from sustainable aviation fuel at any blend from 0% to 100%. A comparison chart ranks the route across the full 18-aircraft fleet. You can see which type delivers the lowest grams of CO2 per passenger-km for that mission.

Freighters render with zero per-pax figures and surface total-cargo CO2 instead. The whole calculation runs client-side, no API calls, and the modal updates live as you drag the load-factor or SAF sliders.

• Per-class CO2 breakdown with floor-area normalization
• RFI 2.0 (Lee et al. 2021) for honest non-CO2 cruise-altitude warming
• SAF blend slider with lifecycle-emissions accounting 0-100%
• Cross-fleet comparison chart ranks the full aircraft library for the same route

Weight-Shedding Breguet Fuel & CO2 Model

An airliner is heaviest at takeoff and sheds weight every mile as it burns fuel, so it burns more per mile early in a flight and less late. Most quick range tools ignore this and apply one flat rate. Great Circle Pro uses the classic Breguet range equation instead, the same weight-shedding physics a flight-planning department relies on, and the most accurate way to tie fuel to weight and distance.

Because it reproduces every manufacturer's published maximum range exactly, range circles, ETOPS coverage, and reserves all match the spec sheets, while a shorter, lighter sector correctly shows a few percent less fuel and CO2 than a flat rate would. The airplane always burns its real amount; it is a flat rate that over-counts anything short of a full-range flight, most on the ultra-long-haul twins. The endpoints match the brochures; the curve in between bends the way the real airplane flies.

And because carbon follows fuel directly, getting the fuel right gets the CO2 right too. It runs live on every Flight Plan card and in the emissions dashboard, entirely client-side with no API calls.

• Cruise burn follows the real Breguet weight-shedding curve, not a flat rate
• Matches each type's published maximum range, so the range rings match the spec sheets
• Per-type Breguet constant from published operating weights
• Interactive explainer chart with a draggable fuel readout

Closed Airspace Avoidance Routing

Since 2022, a meaningful share of long-haul routing has been shaped less by geography and more by which regions of airspace are actually overflyable. Russia, Belarus, Ukraine FIR, Syria, Libya, Yemen, Sudan, North Korea, and Afghanistan are closed or restricted to most Western carriers, with partial sector restrictions over Iran. A great circle that ignores those closures looks geographically pretty but tells you nothing about how an aircraft will actually fly the route.

Great Circle Pro's Airspace toggle on the Flight Plan tool fixes this. Turn it On and any route whose great circle would cross a restricted region detours around the boundary, recalculating block time, fuel burn, range check, and CO2 against the longer flown arc, not the haversine. The detour is highlighted with an amber chip listing the regions avoided and the added distance, so you always see exactly what changed.

The polygons are curated quarterly against the EASA Conflict Zone Information Bulletins and the FAA Special Federal Aviation Regulations. Every entry traces back to an authoritative public source, so the avoidance pattern reflects current regulatory reality, not folklore. Some zones even carry an altitude floor, so a corridor closed to a turboprop can stay open to a jet overhead. The toggle defaults Off so users who want the geographic ideal keep it; turn it On when you want to model the operational reality.

• Off/On toggle on the Flight Plan tool
• Real filed airline routing where one is known for the pair, an efficient estimate otherwise
• Side-by-side comparison of the detour against the plain great circle
• Block time, fuel, range check, and CO2 all recalculated against detoured nm
• Polygons sourced from EASA CZIBs and FAA SFARs, reviewed quarterly

Aviation Route Planning Guides & Analysis

The Great Circle Pro blog covers the methodology, math, and real-world application behind every tool on the platform. Articles range from introductory explainers on why great circle routes look curved on flat maps to deep dives into ETOPS regulatory history, polar routing economics, and the aerodynamics that determine payload-range trade-offs on long-haul widebodies.

Recent posts have examined why Great Circle Pro uses the 85th percentile as a conservative ETOPS sensitivity view, why the Boeing 787 and Airbus A350 opened previously uneconomical city pairs, and how range circle analysis can reveal which airports are genuinely competitive as connecting hubs versus which ones only appear that way due to Mercator projection distortion. Each post is written for readers who already understand the basics of commercial aviation and want to go deeper.

The blog also tracks new features as they are added to Great Circle Pro, with worked examples showing exactly how to use new capabilities in real planning scenarios. If you have used the tool to analyze a specific route or identify an interesting great circle anomaly, the blog is the best place to find the context that makes those observations meaningful. Posts are published regularly as new analytical techniques and route planning methodologies are added to the platform.

• In-depth methodology articles on great circle routing and wind modeling
• ETOPS regulatory analysis and polar routing economics
• Worked examples using real routes and real aircraft performance data
• Feature announcements with step-by-step usage guides