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Rankings / Routes / Los Angeles to Chicago

2025 flights

Los Angeles to Chicago

Between Los Angeles and Chicago, 3.7 million passengers flew nonstop in 2025, on 24 thousand flights of about 1,739 miles and 3.7 hours in the air. The average passenger accounted for about 225 kg of CO2 from the fuel burned, from 168 kg on Frontier Airlines to 230 kg on American Airlines.

  • 225 kgCO2 per passenger, average
  • 1,739 milesabout 3.7 hours in the air
  • 3.7 millionpassengers in 2025
  • 84%of seats filled

CO2 per passenger, airline by airline

CO2 per passenger by airline, Los Angeles to ChicagoBar chart of kilograms of CO2 per passenger on each airline between Los Angeles and Chicago in 2025.050100150200Frontier Airlines168 kgSpirit Airlines179 kgSouthwest Airlines225 kgUnited Airlines228 kgAmerican Airlines230 kg
CO2 per passenger by airline, Los Angeles to ChicagoBar chart of kilograms of CO2 per passenger on each airline between Los Angeles and Chicago in 2025.0100200Frontier Airlines168 kgSpirit Airlines179 kgSouthwest Airlines225 kgUnited Airlines228 kgAmerican Airlines230 kg
Kilograms of CO2 per passenger, one way, 2025. Fuel burned only. Less is better.
Los Angeles to Chicago by airline, 2025
AirlineShare of passengersFlights (thousands)Main aircraftSeats per flightSeats filledkg CO2 per passenger
United Airlines41%9.1Airbus A321neo, Boeing 757-30019683%228
American Airlines35%8.4Boeing 737-800, Boeing 737 MAX 817786%230
Southwest Airlines18%4.8Boeing 737 MAX 8, Boeing 737-70016482%225
Spirit Airlines5%1.1Airbus A320neo, Airbus A321neo20089%179
Frontier Airlines2%0.3Airbus A320neo, Airbus A321neo20487%168

What explains the differences

It's number 16 of the 100 busiest city pairs by passengers, and number 12 for the lowest CO2 per mile flown (0.13 kg per passenger-mile, number 1 being the lowest). A typical route of 1,739 miles in this set comes out at about 242 kg, so this one is 7.4% below it.

The flights use more than one pair of airports: ORD to LAX (64%), ORD to SNA (17%), MDW to LAX (11%). The figures here cover all of them.

The airlines on this route differ by 36% per passenger. Frontier Airlines burned 3,066 gallons per flight and 178 passengers on each, and American Airlines 3,589 gallons and 152 passengers. Fuel burned per flight explains about 51% of the gap and the number of passengers on each flight the other 49%. Frontier Airlines flew 87% full here against 86% for American Airlines, flying mostly Airbus A320neo against Boeing 737-800.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 224 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 0.1% higher.

2019 compared with 2025

In 2019 the route carried 4.2 million passengers on 26 thousand flights. In 2025 it carried 3.7 million, down 14%, on 24 thousand flights, down 8%. The average flight had 181 seats then and 183 now, and 91% of them were filled against 84%.

CO2 per passenger was 234 kg in 2019 and 225 kg in 2025, down 3.9%. Fuel burned per flight was down 10.0% (3,942 gallons to 3,548) and passengers per flight were down 6.3% (165 to 154). The distance flown was about the same (1,740 miles then, 1,739 now).

United Airlines led in both years, with 37% of passengers in 2019 and 41% in 2025. Frontier Airlines didn't have 1% of the passengers in 2019 and now carries 2%. Alaska Airlines no longer reaches 1% of passengers, having had 2% in 2019.

Airline by airline, Spirit Airlines went from 209 kg to 179 kg per passenger (216 seats per flight to 200, main aircraft Airbus A321 then and Airbus A320neo now); Southwest Airlines went from 219 kg to 225 kg per passenger (159 seats per flight to 164, main aircraft Boeing 737-700 then and Boeing 737 MAX 8 now).

Los Angeles to Chicago, 2019 and 2025
Measure20192025
Passengers (thousands)4,2373,658
Flights (thousands)25.823.7
Seats filled91%84%
Gallons of fuel per flight3,9423,548
kg CO2 per passenger234225
CO2 per passenger by airline, 2019 and 2025, Los Angeles to ChicagoBar chart of kilograms of CO2 per passenger on Los Angeles to Chicago for each major airline in 2019 and in 2025.0100200United Airlines 2019241 kgUnited Airlines 2025228 kgAmerican Airlines 2019236 kgAmerican Airlines 2025230 kgSouthwest Airlines 2019219 kgSouthwest Airlines 2025225 kgSpirit Airlines 2019209 kgSpirit Airlines 2025179 kg
CO2 per passenger by airline, 2019 and 2025, Los Angeles to ChicagoBar chart of kilograms of CO2 per passenger on Los Angeles to Chicago for each major airline in 2019 and in 2025.0100200United Airlines 2019241 kgUnited Airlines 2025228 kgAmerican Airlines 2019236 kgAmerican Airlines 2025230 kgSouthwest Airlines 2019219 kgSouthwest Airlines 2025225 kgSpirit Airlines 2019209 kgSpirit Airlines 2025179 kg
Kilograms of CO2 per passenger on the airlines that flew the route in both years. 2019 figures use that year's filings and estimated aircraft fuel rates, with type-average replacements for missing or outlying filings as described in the methodology. Less is better.

Los Angeles to Chicago and back: time in the air

Flights from Chicago to Los Angeles spent 232 minutes in the air on average in 2025, against 208 minutes from Los Angeles to Chicago: 24 minutes longer, 11% more. That's the westbound direction, into the prevailing west-to-east winds, which at flight levels often blow at well over 50 miles an hour.

At this route's average burn of about 967 gallons per flight hour, those extra minutes cost about 385 gallons per flight, which is about 2.5 gallons or 24 kg of CO2 for each passenger on the slower direction. The route figure above averages both directions.

Time in the air by direction, 2025
DirectionAverage minutes in the airFlights
Chicago to Los Angeles232.111,894
Los Angeles to Chicago208.211,846

Fly or drive

Driving is about 2,035 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 604 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 169% more than the 225 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (201 kg each, and 151 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 802 kg per vehicle.

CO2 per person by way of travel, Los Angeles to ChicagoBar chart of kilograms of CO2 per person flying, driving or taking the train between Los Angeles and Chicago.0200400600Flight, average225 kgCar, driver alone604 kgCar, 2 people302 kgCar, 4 people151 kg
CO2 per person by way of travel, Los Angeles to ChicagoBar chart of kilograms of CO2 per person flying, driving or taking the train between Los Angeles and Chicago.0200400600Flight, average225 kgCar, driver alone604 kgCar, 2 people302 kgCar, 4 people151 kg
CO2 per person, Los Angeles to Chicago. Driving figures divide one car's emissions between the people in it. See flying vs driving for other trip lengths.

Flights are listed under the airline that operates them, so regional flying appears under the regional. How the CO2 and drive figures are worked out is in the methodology.

Routes with shared cities or nearby CO2 per mile

Los Angeles to San Francisco75 kg CO2 per passenger over 337 milesNew York to Chicago125 kg CO2 per passenger over 730 milesLos Angeles to Las Vegas53 kg CO2 per passenger over 227 milesNew York to Los Angeles406 kg CO2 per passenger over 2,465 milesChicago to Seattle220 kg CO2 per passenger over 1,722 milesChicago to Las Vegas194 kg CO2 per passenger over 1,516 milesDenver to Washington, DC192 kg CO2 per passenger over 1,471 milesAtlanta to Las Vegas229 kg CO2 per passenger over 1,747 miles

Airports on this route: O'Hare International Airport, Los Angeles International Airport, John Wayne Airport, Midway International Airport.

Airport and airline references

Source: US Bureau of Transportation Statistics (BTS), T-100 traffic and Schedule T-2 fuel filings; US EPA transport emission factors. See the methodology.

See all routes, or how the airlines compare overall on the airline pages.