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2025 flights

Chicago to Las Vegas

Between Chicago and Las Vegas, 2.3 million passengers flew nonstop in 2025, on 16 thousand flights of about 1,516 miles and 3.2 hours in the air. The average passenger accounted for about 194 kg of CO2 from the fuel burned, from 166 kg on Spirit Airlines to 211 kg on American Airlines.

  • 194 kgCO2 per passenger, average
  • 1,516 milesabout 3.2 hours in the air
  • 2.3 millionpassengers in 2025
  • 83%of seats filled

CO2 per passenger, airline by airline

CO2 per passenger by airline, Chicago to Las VegasBar chart of kilograms of CO2 per passenger on each airline between Chicago and Las Vegas in 2025.050100150200Spirit Airlines166 kgFrontier Airlines172 kgSouthwest Airlines190 kgUnited Airlines196 kgAmerican Airlines211 kg
CO2 per passenger by airline, Chicago to Las VegasBar chart of kilograms of CO2 per passenger on each airline between Chicago and Las Vegas in 2025.0100200Spirit Airlines166 kgFrontier Airlines172 kgSouthwest Airlines190 kgUnited Airlines196 kgAmerican Airlines211 kg
Kilograms of CO2 per passenger, one way, 2025. Fuel burned only. Less is better.
Chicago to Las Vegas by airline, 2025
AirlineShare of passengersFlights (thousands)Main aircraftSeats per flightSeats filledkg CO2 per passenger
Southwest Airlines38%6.2Boeing 737 MAX 8, Boeing 737-80016983%190
United Airlines29%4.4Boeing 737-900ER, Airbus A321neo18582%196
American Airlines21%3.3Boeing 737-800, Boeing 737 MAX 817484%211
Spirit Airlines8%1.1Airbus A320neo, Airbus A320-20018885%166
Frontier Airlines4%0.6Airbus A320neo, Airbus A321neo20178%172

What explains the differences

It's number 54 of the 100 busiest city pairs by passengers, and number 11 for the lowest CO2 per mile flown (0.13 kg per passenger-mile, number 1 being the lowest). A typical route of 1,516 miles in this set comes out at about 215 kg, so this one is 9.8% below it.

The flights use more than one pair of airports: ORD to LAS (68%), MDW to LAS (32%). The figures here cover all of them.

The airlines on this route differ by 28% per passenger. Spirit Airlines burned 2,727 gallons per flight and 161 passengers on each, and American Airlines 3,175 gallons and 146 passengers. Fuel burned per flight explains about 62% of the gap and the number of passengers on each flight the other 38%. Spirit Airlines flew 85% full here against 84% 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 196 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 0.9% lower.

2019 compared with 2025

In 2019 the route carried 2.4 million passengers on 15 thousand flights. In 2025 it carried 2.3 million, down 4%, on 16 thousand flights, up 5%. The average flight had 174 seats then and 177 now, and 91% of them were filled against 83%.

CO2 per passenger was 190 kg in 2019 and 194 kg in 2025, up 2.1%. Fuel burned per flight was down 6.1% (3,098 gallons to 2,907) and passengers per flight were down 8.0% (159 to 146). The distance flown was about the same (1,517 miles then, 1,516 now).

Southwest Airlines led in both years, with 34% of passengers in 2019 and 38% in 2025. United Airlines gained the most share, 25% to 29%. Spirit Airlines lost the most, 16% to 8%.

Airline by airline, United Airlines went from 201 kg to 196 kg per passenger (177 seats per flight to 185, main aircraft Boeing 737-900ER in both years); Southwest Airlines went from 186 kg to 190 kg per passenger (165 seats per flight to 169, main aircraft Boeing 737-800 then and Boeing 737 MAX 8 now).

Chicago to Las Vegas, 2019 and 2025
Measure20192025
Passengers (thousands)2,3752,289
Flights (thousands)14.915.7
Seats filled91%83%
Gallons of fuel per flight3,0982,907
kg CO2 per passenger190194
CO2 per passenger by airline, 2019 and 2025, Chicago to Las VegasBar chart of kilograms of CO2 per passenger on Chicago to Las Vegas for each major airline in 2019 and in 2025.050100150200Southwest Airlines 2019186 kgSouthwest Airlines 2025190 kgUnited Airlines 2019201 kgUnited Airlines 2025196 kgAmerican Airlines 2019211 kgAmerican Airlines 2025211 kgSpirit Airlines 2019166 kgSpirit Airlines 2025166 kg
CO2 per passenger by airline, 2019 and 2025, Chicago to Las VegasBar chart of kilograms of CO2 per passenger on Chicago to Las Vegas for each major airline in 2019 and in 2025.0100200Southwest Airlines 2019186 kgSouthwest Airlines 2025190 kgUnited Airlines 2019201 kgUnited Airlines 2025196 kgAmerican Airlines 2019211 kgAmerican Airlines 2025211 kgSpirit Airlines 2019166 kgSpirit Airlines 2025166 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.

Chicago to Las Vegas and back: time in the air

Flights from Chicago to Las Vegas spent 206 minutes in the air on average in 2025, against 181 minutes from Las Vegas to Chicago: 24 minutes longer, 13% 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 901 gallons per flight hour, those extra minutes cost about 365 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 Las Vegas205.77,821
Las Vegas to Chicago181.47,829

Fly or drive

Driving is about 1,774 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 527 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 172% more than the 194 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (176 kg each, and 132 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 699 kg per vehicle.

CO2 per person by way of travel, Chicago to Las VegasBar chart of kilograms of CO2 per person flying, driving or taking the train between Chicago and Las Vegas.0200400Flight, average194 kgCar, driver alone527 kgCar, 2 people263 kgCar, 4 people132 kg
CO2 per person by way of travel, Chicago to Las VegasBar chart of kilograms of CO2 per person flying, driving or taking the train between Chicago and Las Vegas.0200400Flight, average194 kgCar, driver alone527 kgCar, 2 people263 kgCar, 4 people132 kg
CO2 per person, Chicago to Las Vegas. 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

New York to Chicago125 kg CO2 per passenger over 730 milesLos Angeles to Las Vegas53 kg CO2 per passenger over 227 milesSan Francisco to Las Vegas71 kg CO2 per passenger over 404 milesLos Angeles to Chicago225 kg CO2 per passenger over 1,739 milesChicago to San Francisco235 kg CO2 per passenger over 1,845 milesChicago to Seattle220 kg CO2 per passenger over 1,722 milesDenver to Washington, DC192 kg CO2 per passenger over 1,471 miles

Airports on this route: O'Hare International Airport, Harry Reid International 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.