What Is a Below Average CO2 Flight? (2026 Data)

Next to many fares on a flight search page sits a small label: lower, typical or higher emissions. It does not compare your flight with every flight in the world. It compares it with the other flights on the same route. A Zurich to London flight estimated at 185 lb (84 kg¹) of CO2e per passenger is marked as lower than typical because the typical flight on that route comes to 198 lb (90 kg¹).¹ CO2e, carbon dioxide equivalent, counts the CO2 from burning jet fuel plus small amounts of other greenhouse gases.

This page explains how that label is set and then puts numbers on the flight itself: CO2 per passenger from the shortest hops to long-haul trips, what the cabin you book does to your share, how much fuel different aircraft burn, and how the US total has moved since 1990, when US air carriers burned 16.15 billion gallons² of jet fuel. In 2025 they burned 20.47 billion², the highest year in a series that starts in 1990.² The chart below shows the scale first: one economy seat on one aircraft type, from a short hop to a long-haul trip.

What does below average CO2 mean on a flight?

A below average CO2 flight is one whose estimated emissions per passenger sit under the typical value for its own route, not under a national or global average.¹ The typical value is worked out per market, meaning an origin and destination pair, and it is a weighted median, not a mean.¹ To build it, every route that serves the market is collected, including routes from nearby airports within 150 km¹ (93 miles). A route has to operate on at least 20¹ days a year to count. Routes that are unreasonably slow are removed: anything with an effective speed under 75 km/h¹ (47 mph), and anything longer than a set multiple of the fastest option, 1.25¹ times plus 1 hour on short-haul markets, 1.5¹ times plus 2 hours on medium-haul and 1.75¹ times plus 2 hours on long-haul. Of the routes left, the 20¹ fastest are kept, and the median of their emissions is taken with each route weighted by how many days a year it operates.¹ The worked example below shows why the weighting matters.

Four routes emit different amounts per passenger, but one of them flies on 200¹ of the 380¹ operating days in the market, so its 120 kg¹ becomes the typical value.

Airline-reported labels since July 2025

The estimate behind the label is not always a model. Since July 2025, where an airline has published a flight emissions label under European Union rules, that airline-reported figure is used in place of the modeled estimate; the model remains the fallback for every other flight.⁵ The European label rests on the airline's own fuel and operating data and is set up by the regulation on sustainable aviation fuel.⁶ The comparison with the route's typical value works the same way whichever estimate is used.

A higher label is the mirror image, and cabin class moves it more than anything else on the same route.

What an above average CO2 flight label means

Such a flight is estimated to emit more per passenger than the typical flight on its route. The flight may use an older or less efficient aircraft, fly a longer routing, or carry fewer passengers per seat of floor area. The fare class matters as well: premium seats take up more cabin floor, so each one is assigned a larger share of the flight's emissions, and the same flight can show a higher estimate in business than in economy.⁴

The shares follow fixed seat-area weights. On a wide-body jet a premium economy seat counts as 1.5⁴ economy seats, a business seat as 4⁴ and a first class seat as 5⁴. On a narrow-body jet, where premium seats are closer in size to economy, business and first both count as 1.5⁴.⁴

What does average CO2 mean on a flight?

On a flight label, average means typical for that route: the weighted median described above. There is no single average that applies to every flight, because the number depends on the distance, the aircraft, the cabin and the rules used to turn fuel into CO2e. The main inputs are published.⁴

Burning one kilogram of jet fuel releases 3.1894 kg⁴ of CO2e at the engine. Producing and delivering that fuel adds 0.6465 kg⁴, for 3.8359 kg⁴ from well to wake. When the actual load is not known, 84.5%⁴ of seats are assumed to be filled, and belly cargo takes its share by weight, 8%⁴ of the flight's emissions in the published worked example. Real flight paths average about 5.2%⁴ longer than the straight great-circle line between airports, and a passenger's airport visits add 1.71 kg⁴ of CO2 each.⁴

Other published methods make different choices. One uses 3.16⁷ kg of CO2 per kilogram of fuel and adds 50⁷ to 125 km⁷ to the great-circle distance depending on trip length.⁷ Another adds 8%⁸ to distance and offers a version with an uplift for the warming effect of contrails and other non-CO2 emissions.⁸ These choices explain most of the gap between estimates for the same trip.

How much of a flight is put on the passengers depends on the route. The method that uses 3.16 kg of CO2 per kilogram of fuel splits each flight by weight: every passenger counts as 100 kg⁷ with baggage, plus 50 kg⁷ per seat for seats, galleys and crew, and the cargo and mail in the hold take the rest.⁷ On international flights within North America, such as between the US and Canada, passengers are assigned 93.35%⁷ of the emissions; US domestic flights use a separate domestic factor that is not published. Between North America and North Asia, where cargo and mail make up more of the load, 66.44%⁷.⁷ These shares come from 2016 traffic, the basis of the current calculator version, which also assumes 79.1%⁷ of seats filled on international flights within North America and 83.1%⁷ between Europe and North America.⁷

CO2 emissions per flight per person

Distance comes first. To show how much it matters, we applied the published method to one aircraft type, a Boeing 787-9 with a fixed seat layout, at the four trip lengths its published fuel table covers. The result is our calculation and illustrative: one aircraft type (Boeing 787-9), not real named routes. An economy seat comes to 76.0 kg³ of CO2e from well to wake on a 500-nautical-mile flight (575 miles) and 606.0 kg³ at 5,500 nautical miles (6,329 miles), about 7.97³ times as much for 11 times the distance, as the chart near the top of this page shows.^{4 3} The fixed fuel for taking off and landing, 1,638 kg⁴ on this aircraft, weighs more on short trips.

Is a below average CO2 flight good or bad?

It is better than the alternatives on the same route, and that is all the label says. Picking the lower-emitting of two nonstop flights between the same cities saves a few kilograms per passenger in the worked example, 84 against 90 kg. The distance flown and the cabin booked move the total far more: on a long-haul flight a business seat carries about 1,662.5 kg³ more CO2e than an economy seat on the same aircraft in our Boeing 787-9 example. A label of below average on a long flight can still mean more CO2 than a typical short one.

How much CO2 does a long-haul flight produce?

In the same Boeing 787-9 example, our calculation puts an economy seat on a 5,000-nautical-mile flight (5,754 miles) at 554.1 kg³ of CO2e, about 1,220 lb³. A premium economy seat on that flight comes to 831.2 kg³, a business seat to 2,216.6 kg³ and a first class seat to 2,770.7 kg³: 4.0³ and 5.0³ times the economy figure, the wide-body seat weights at work.^{3 4} This is an illustration for one aircraft type with a fixed layout; the same trip on a denser or emptier aircraft gives a different number.

How much CO2 does a 1-hour flight produce?

Flight time is not an input to the published fuel tables; distance is, so the shortest trips are measured here by distance. Take a 250-nautical-mile trip (288 miles). Per passenger, the US short-haul factor of 0.207 kg of CO2 per passenger-mile works out to about 60 kg³ of CO2 for that distance, our calculation.^{9 3} For the whole aircraft, a turboprop such as the ATR 72 burns 891 kg⁷ of fuel for the whole flight, while a Boeing 757-200 burns 4,435 kg⁷, about 4.98³ times as much.⁷ Each kilogram of jet fuel makes 3.16⁷ kg of CO2, so an Airbus A320neo at that distance, burning 2,360 kg⁷, emits about 7,460 kg³ of CO2 for the whole aircraft before it is shared among the passengers and cargo on board.⁷ Larger aircraft carry more seats, so these whole-flight figures are not a per-passenger ranking.

From 250 nautical miles up, the newer narrow-body models burn less than the aircraft they replace; at 125⁷ nautical miles the A320neo and A321neo burn slightly more than the A320 and A321.⁷ In the fuel table the short-distance values for the newest types come from a separate formula, so the fair comparison is at longer distances. At 1,000⁷ nautical miles (1,151 miles) the A320neo needs 6,236 kg⁷ against 7,772 kg⁷ for the older A320, 20%³ less.^{7 3}

At 2,000 nautical miles (2,302 miles), the A320neo burns 11,497 kg⁷ against 13,648 kg⁷ for the A320, 16%³ less, and the 737 MAX 8 11,258 kg⁷ against 13,460 kg⁷ for the 737-800. The 757-200 burns 17,740 kg⁷.⁷

The same types at other distances: at 1,500⁷ nautical miles (1,726 miles) the 757-200 burns 13,984 kg⁷, the A321neo 9,794 kg⁷ and the ATR 72 turboprop 3,891 kg⁷; at 3,000⁷ nautical miles (3,452 miles) the A321neo needs 19,941 kg⁷ and the 737 MAX 8 16,408 kg⁷.⁷

On long-haul trips the aircraft are larger and the totals climb. At 5,000 nautical miles a Boeing 787-9 burns 60,142 kg⁷ of fuel, about 190,000 kg³ of CO2 for the whole flight, and an Airbus A380 burns 148,512 kg⁷, 2.69³ times the 55,286 kg⁷ of a Boeing 787-8.⁷ Divided among a few hundred passengers and the belly cargo, that whole-flight total becomes the per-seat figures shown earlier.

Fuel keeps climbing with distance. At 3,000⁷ nautical miles (3,452 miles) a Boeing 787-9 burns 36,472 kg⁷ and an Airbus A380 90,143 kg⁷; at 6,000⁷ nautical miles (6,905 miles) the 787-9 needs 71,977 kg⁷.⁷

CO2 per passenger-mile and per passenger-km

To compare trips of any length, divide the CO2 emissions per flight, per person, per km or per mile. The US reference factors for business travel give 0.207 kg⁹ of CO2 per passenger-mile for flights under 300 miles, 0.129 kg⁹ for flights of 300 to 2,300 miles and 0.163 kg⁹ beyond that.⁹ Short flights come out highest per mile. Take-off and landing use a fixed amount of fuel whatever the distance, 1,638 kg⁴ on a Boeing 787-9.⁴

All three are combustion-only factors, and each gas is listed separately: methane and nitrous oxide add grams, not kilograms, per passenger-mile.⁹

Per kilometer, factors that count the wider warming effect of flying are higher. With an uplift for contrails and other non-CO2 effects, a domestic flight within the UK comes to 229.3 g³ of CO2e per passenger-km and a long-haul flight to 152.8 g³.⁸ Without the uplift, the domestic factor is 135.5 g³, 59.1%³ of the uplifted one, and producing and delivering the fuel adds another 33.5 g³.⁸ Every one of these factors already includes an 8%⁸ allowance for indirect routing.

Our Boeing 787-9 example lands lower, at 59.8 g³ per passenger-km for an economy seat on a 5,000-nautical-mile flight, well to wake.³ The two are built differently: the per-km factors add 8% to the distance for routing and average a whole fleet, while the example is one new aircraft type with no routing allowance that assigns 8% of the flight's emissions to cargo.^{8 4 3}

Cabin class matters just as much per kilometer. With the non-CO2 uplift, a long-haul business seat comes to 339.4 g³ per passenger-km against 117.0 g³ in economy, 2.9³ times as much; first class reaches 468.1 g³.⁸

From one seat to a whole country's fleet.

US flying in total: fuel and CO2 since 1990

The national figures behind average flight CO2 emissions are totals: the fuel US air carriers burn and the CO2 that all aircraft emit in a year. US air carriers that report fuel, passenger and all-cargo airlines alike, burned 20.47 billion gallons² of jet fuel in 2025, the highest year in the series, which starts in 1990.² The largest carriers used 97.9%³ of it.²

The low point was 2020, when fuel use fell to 11.48 billion gallons², 59.8%³ of the 2019 level. Use was back to 20.34 billion² by 2024. Fitting a straight line to 2010-2025 and extending it gives about 21.83 billion gallons³ in 2050; this is our calculation, not a forecast.³

CO2 from US aircraft by type of flying

Inside the country, commercial aircraft emitted 130.8¹⁰ million metric tons of CO2e in 2023, the same as in 2022.¹⁰ Commercial CO2 rose 18%¹¹ from 1990 to 2023, while military aircraft emissions fell 68%¹¹.¹¹ Here commercial aircraft means passenger, cargo and charter flights together.¹¹ General aviation, the private and small business aircraft, jumped from 24.5¹⁰ to 39.5¹⁰ million metric tons in 2023.

Almost all general aviation emissions come from jet fuel: 38.0¹⁰ of the 39.5 million metric tons in 2023, with aviation gasoline adding 1.5¹⁰ million, down from 3.2¹⁰ million in 1990.¹⁰

International departures from the US are counted separately

The national total leaves out fuel bought in the US by aircraft departing on international flights. That fuel is reported on its own line: commercial international departures from the US emitted 63.5¹¹ million metric tons of CO2 in 2022, and the inventory carries the same figure into 2023 because newer fuel data were not yet available.¹¹ That is 49.0%³ of the 129.7¹¹ million from commercial flights within the country in 2023 (a CO2-only figure, which is why it sits just below the 130.8 million of CO2e above), and 2.12³ times the 30.0¹¹ million of 1990.¹¹ All international aviation departing the US, military included, emitted 74.1%¹¹ more in 2023 than in 1990.¹¹

Measured as energy, US and foreign airlines used 902¹¹ trillion Btu of jet fuel on international departures from the US in 2022, against 426¹¹ trillion in 1990; military international flights used 42¹¹ trillion in 2023.¹¹

Nitrous oxide from the engines adds a little on top of the CO2: 1.5¹¹ million metric tons of CO2e from aircraft within the US in 2023 and 0.6¹¹ million from international aviation departures.¹¹

Context: freight's share of commercial aircraft emissions

Commercial aircraft carry freight as well as people, and the national accounts split their emissions by weight, counting each passenger at 150 lb with 50 lb of luggage.¹⁰ In 2023 passengers accounted for 112.6¹⁰ million metric tons of the 130.8 million, and freight for the other 13.9%³. In 2020, when passenger emissions fell from 118.5¹⁰ to 64.2¹⁰ million, freight's share reached 30.2%³.¹⁰

Where jet fuel is sold: a state map

Jet fuel sold in the US in 2024 released 253,356¹² thousand metric tons of CO2 when burned.¹² The map counts fuel by the state where it was sold, which follows the big airports and hubs, not the airspace a flight crosses or the states its passengers live in. California led with 38,292¹² thousand metric tons, ahead of Florida at 24,916¹² and Texas at 22,735¹²; Alaska ranked seventh at 9,217¹².¹² West Virginia had the least, at 88¹².

Flying's share of US transportation CO2

Within the US, commercial flying is a single-digit share of transportation CO2: 7%¹¹ in 2023.¹¹ International departures are outside that total, as explained above.

Over three decades the share has moved up and down. All aircraft, commercial, private and military, made up 12.4%³ of US domestic transportation CO2 in 1990, 7.6%³ in 2020 and 10.0%³ in 2023.¹⁰ For flights between countries, the 193¹³ member states of the UN aviation body adopted a collective goal in 2022 of net-zero CO2 from international aviation by 2050.¹³

What the label means for your trip

For one traveler, the choices rank in a clear order. The route's typical value and the label around it move the estimate by a few kilograms in the worked example. The cabin moves it by a factor of up to 5⁴ on a wide-body jet.⁴ Distance moves it most: from 76.0 kg³ to 606.0 kg³ per economy seat across the trip lengths in our Boeing 787-9 example.³

A label is still useful. On a route with several nonstop options, it points to the lower-emitting aircraft and schedule at no cost in distance, and where airlines publish their own verified figures, the estimate rests on their actual fuel data.⁵ What it cannot do is tell you whether a trip is worth its CO2; for that, the per-passenger numbers above are the better guide.

Comparison: rail, bus and private jets

The same US reference factors cover trains and buses. A bus passenger-mile comes to 0.066 kg⁹ of CO2, so a flight under 300 miles emits 3.14³ times as much per mile; intercity rail averages 0.096 kg⁹, and the electrified Northeast Corridor 0.023 kg⁹.⁹ All of these are combustion-only factors.

The average CO2 emissions per private jet flight were about 5.15 metric tons¹⁴ of CO2e worldwide in 2023, a bottom-up estimate that adds up to 18.4 million¹⁴ metric tons for the year. An hour of US private jet flying burned an average of 930.8 kg¹⁴ of fuel, about 2.94³ metric tons of CO2e.¹⁴ A typical private jet emits about 810¹⁴ metric tons a year, and the world's private jets emitted 19.5¹⁴ million metric tons of CO2e in 2023 in the top-down estimate.¹⁴ In our Boeing 787-9 example, even a business seat on a 5,000-nautical-mile flight comes to less than one average private jet flight.

Conclusions

1. The label is a comparison within one route, not a verdict on the flight. In the worked example the lower label separates 84 kg from 90 kg per passenger, while our Boeing 787-9 example puts a long-haul economy seat at 554.1 kg.^{1 3}
2. Where you sit can matter more than which flight you pick. On a wide-body jet a business seat is weighted 4 times an economy seat and a first class seat 5 times, far more than the gap between flights on one route.⁴
3. Newer aircraft burn less on the same trip. At 2,000 nautical miles the A320neo needs 11,497 kg of fuel against 13,648 kg for the A320 it replaces, 16% less.⁷
4. US flying is back above its old peak. US air carriers burned 20.47 billion gallons of jet fuel in 2025, and international departures from the US, outside the national total, emitted 63.5 million metric tons of CO2 in 2022, 2.12 times 1990; the latest US inventory carries the same figure into 2023.^{2 11}