Rankings / United Airlines
2025 report cardUnited Airlines
In 2025 United Airlines flew 58.2 passenger-miles per gallon of jet fuel, ranking 11 of 13. That's 4% worse than the all-airline figure that year. Since 2000 its figure has risen 46%.
About United Airlines
United flies from hubs at Chicago, Denver, Houston, Newark, San Francisco, Los Angeles and Washington Dulles, and it's one of the three biggest airlines in this data. It merged with Continental in 2010, and BTS began counting the two as one filer in 2012. Regional partners operate part of its schedule under the United Express name, and that flying is included here on an estimated basis.
- 58.2passenger-miles per gallon, 2025
- 0.167 kgCO2 per passenger-mile
- 82%of seats filled
- 126seats per flight on average
The story in the figures
United Airlines' passenger-miles per gallon rose 46% between 2000 and 2025, from 39.8 to 58.2. Most of that came from the aircraft: seat-miles per gallon rose 29%, while planes ran fuller, with 72% of seat-miles filled in 2000 against 82% in 2025.
The shape of the flying changed as well: the average flight went from 139 seats to 126. In general, smaller aircraft burn more fuel per seat.
Its best year was 2023, at 58.7 passenger-miles per gallon, and its latest figure sits 0.8% below that.
In 2020 the pandemic emptied the cabins: load factor dropped from 84% to 60%, and passenger-miles per gallon fell from 56.8 to 40.9. A flight burns most of its fuel whether the seats are full or not, which is why an empty year looks so bad per passenger. By 2025 the figure was 2.5% above its 2019 level.
Against the all-airline figure for 2025 (60.6), United Airlines was 3.8% worse. On a 1,000 mile trip that works out to 167 kg of CO2 for one passenger, from burning jet fuel only.
What one seat costs the climate
CO2 for one passenger on United Airlines, from burning jet fuel only.
- 84 kgover 500 miles
- 167 kgover 1,000 miles
- 335 kgover 2,000 miles
United Airlines sells seats on flights operated by regional partners, mainly SkyWest Airlines, Mesa Airlines, and Republic Airways. In 2025 about 6.7% of its seat-miles were flown by regionals. How much of each regional's flying belongs to United Airlines is an estimate based on the hubs the regional serves. The figure for 2025 sits between 58.2 and 58.3 passenger-miles per gallon depending on how multi-airline regionals are split. See the methodology.
BTS began combining United and Continental filings in January 2012. Continental Airlines has its own page for 2000 to 2011, so the United line includes Continental from 2012 on.
Year-by-year figures
| Year | Passenger-miles per gallon | kg CO2 per passenger-mile | Seat-miles per gallon | Load factor | Passengers (millions) | Fuel (million gallons) | CO2 (thousand tonnes) |
|---|---|---|---|---|---|---|---|
| 2025 | 58.2 | 0.167 | 71.0 | 82.1% | 184.0 | 4,674 | 45,572 |
| 2024 | 58.6 | 0.166 | 70.6 | 83.0% | 171.9 | 4,390 | 42,800 |
| 2023 | 58.7 | 0.166 | 70.0 | 83.8% | 162.3 | 4,129 | 40,261 |
| 2022 | 58.5 | 0.167 | 70.2 | 83.4% | 137.3 | 3,460 | 33,734 |
| 2021 | 50.1 | 0.195 | 69.9 | 71.6% | 90.7 | 2,404 | 23,435 |
| 2020 | 40.9 | 0.238 | 68.3 | 59.9% | 46.9 | 1,642 | 16,009 |
| 2019 | 56.8 | 0.172 | 67.6 | 84.1% | 146.1 | 4,021 | 39,206 |
| 2018 | 56.7 | 0.172 | 67.8 | 83.6% | 141.9 | 3,871 | 37,741 |
| 2017 | 55.7 | 0.175 | 67.5 | 82.5% | 132.8 | 3,701 | 36,089 |
| 2016 | 55.2 | 0.177 | 66.7 | 82.9% | 121.3 | 3,552 | 34,628 |
| 2015 | 54.8 | 0.178 | 65.6 | 83.4% | 118.8 | 3,557 | 34,677 |
| 2014 | 53.5 | 0.182 | 64.1 | 83.6% | 120.6 | 3,617 | 35,268 |
| 2013 | 52.7 | 0.185 | 63.0 | 83.7% | 121.1 | 3,654 | 35,628 |
| 2012 | 51.6 | 0.189 | 62.4 | 82.7% | 130.1 | 3,807 | 37,118 |
| 2011 | 50.8 | 0.192 | 60.6 | 83.7% | 60.3 | 2,021 | 19,709 |
| 2010 | 50.5 | 0.193 | 60.3 | 83.6% | 69.4 | 2,138 | 20,850 |
| 2009 | 48.8 | 0.200 | 60.0 | 81.3% | 78.0 | 2,233 | 21,776 |
| 2008 | 47.8 | 0.204 | 59.4 | 80.5% | 84.8 | 2,476 | 24,138 |
| 2007 | 49.3 | 0.198 | 60.0 | 82.3% | 92.4 | 2,572 | 25,080 |
| 2006 | 48.2 | 0.202 | 59.0 | 81.7% | 93.5 | 2,608 | 25,431 |
| 2005 | 47.5 | 0.205 | 58.8 | 80.8% | 90.8 | 2,574 | 25,095 |
| 2004 | 46.3 | 0.211 | 58.9 | 78.6% | 90.1 | 2,587 | 25,224 |
| 2003 | 44.9 | 0.217 | 58.8 | 76.3% | 78.1 | 2,364 | 23,050 |
| 2002 | 43.0 | 0.227 | 58.5 | 73.5% | 74.1 | 2,535 | 24,713 |
| 2001 | 39.5 | 0.247 | 55.9 | 70.7% | 79.6 | 2,911 | 28,381 |
| 2000 | 39.8 | 0.245 | 55.2 | 72.1% | 88.6 | 3,156 | 30,773 |
The United Airlines fleet
United Airlines operated 1,058 passenger aircraft of its own in 2025. The regional airlines that fly for it file their own fleets. The average age was 15.0 years: 27% of the aircraft were under five years old and 44% were twenty or older. The oldest was a Boeing 767-300 built in 1991. That's the 10th youngest of the 12 airlines ranked here.
In 2006 the average age was 11.3 years across 460 aircraft. It's older now by 3.7 years, and the fleet is bigger.
On the Boeing 737-900 and 900ER, United Airlines fits 173 seats on average, against a median of 181 at the other airlines that fly it (179 to 181). Seats on the same aircraft are one reason fuel per seat and fuel per passenger differ between airlines: the fuel burned by a given plane is much the same, and more seats share it.
United Airlines aircraft by model, 2025
| Model | Aircraft | Average seats | Other airlines, median seats | Average age |
|---|---|---|---|---|
| Boeing 737-900 and 900ER | 148 | 173 | 181 | 13.4 |
| Boeing 737-800 | 141 | 154 | 175 | 21.5 |
| Boeing 737 MAX 8 | 123 | 164 | 175 | 2.0 |
| Boeing 737 MAX 9 | 120 | 179 | 178 | 2.6 |
| Airbus A319 | 76 | 120 | 132 | 23.5 |
| Boeing 777-200 | 74 | 273 | 273 | 26.0 |
| Airbus A320 | 68 | 142 | 161 | 25.2 |
| Airbus A321neo | 51 | 220 | 194 | 0.6 |
| Boeing 787-9 | 48 | 219 | 271 | 6.2 |
| Boeing 757-200 | 40 | 169 | 193 | 28.4 |
| Boeing 737-700 | 40 | 124 | 143 | 26.3 |
| Boeing 767-300 | 37 | 198 | 215 | 29.3 |
| Boeing 777-300ER | 22 | 276 | 304 | 7.5 |
| Boeing 757-300 | 21 | 216 | 234 | 22.8 |
| Boeing 787-10 | 21 | 337 | 4.9 | |
| Boeing 767-400 | 16 | 235 | 238 | 23.6 |
| Boeing 787-8 | 12 | 219 | 234 | 12.2 |
All the airlines are compared on the fleets page.
Neighbours in the ranking
Nearby airline results
These airlines sit nearby by passenger-miles per gallon in their last data year. Historical airlines have different end years, shown here, so this isn't a same-year ranking.
Airline references
Source: US Bureau of Transportation Statistics (BTS), Schedule P-12(a) fuel, T-100 traffic and regional Schedule T-2 filings; US EPA jet-fuel CO2 factor. See the methodology.