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Rankings / Routes / Denver to Salt Lake City

2025 flights

Denver to Salt Lake City

Between Denver and Salt Lake City, 1.8 million passengers flew nonstop in 2025, on 16 thousand flights of about 391 miles and 1.1 hours in the air. The average passenger accounted for about 73 kg of CO2 from the fuel burned, from 52 kg on Frontier Airlines to 112 kg on SkyWest Airlines.

  • 73 kgCO2 per passenger, average
  • 391 milesabout 1.1 hours in the air
  • 1.8 millionpassengers in 2025
  • 80%of seats filled

CO2 per passenger, airline by airline

CO2 per passenger by airline, Denver to Salt Lake CityBar chart of kilograms of CO2 per passenger on each airline between Denver and Salt Lake City in 2025.0255075100Frontier Airlines52 kgSouthwest Airlines67 kgUnited Airlines71 kgDelta Air Lines85 kgSkyWest Airlines112 kg
CO2 per passenger by airline, Denver to Salt Lake CityBar chart of kilograms of CO2 per passenger on each airline between Denver and Salt Lake City in 2025.050100Frontier Airlines52 kgSouthwest Airlines67 kgUnited Airlines71 kgDelta Air Lines85 kgSkyWest Airlines112 kg
Kilograms of CO2 per passenger, one way, 2025. Fuel burned only. Less is better.
Denver to Salt Lake City by airline, 2025
AirlineShare of passengersFlights (thousands)Main aircraftSeats per flightSeats filledkg CO2 per passenger
Southwest Airlines34%4.9Boeing 737-800, Boeing 737 MAX 816579%67
United Airlines20%2.7Airbus A320-200, Boeing 737-80015785%71
Delta Air Lines19%3.3Airbus A319, Airbus A320-20013876%85
Frontier Airlines18%1.9Airbus A320neo, Airbus A321neo21082%52
SkyWest Airlines9%2.8Embraer 1757082%112

What explains the differences

It's number 76 of the 100 busiest city pairs by passengers, and number 81 for the lowest CO2 per mile flown (0.19 kg per passenger-mile, number 1 being the lowest). A typical route of 391 miles in this set comes out at about 77 kg, so this one is 5.2% below it.

The airlines on this route differ by 113% per passenger. Frontier Airlines burned 929 gallons per flight and 173 passengers on each, and SkyWest Airlines 662 gallons and 58 passengers. The gap comes from how many passengers share each flight, not from fuel burned per flight. Frontier Airlines flew 82% full here against 82% for SkyWest Airlines, flying mostly Airbus A320neo against Embraer 175.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 50 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 44% higher.

2019 compared with 2025

In 2019 the route carried 1.5 million passengers on 15 thousand flights. In 2025 it carried 1.8 million, up 20%, on 16 thousand flights, up 5%. The average flight had 120 seats then and 146 now, and 86% of them were filled against 80%.

CO2 per passenger was 77 kg in 2019 and 73 kg in 2025, down 5.7%. Fuel burned per flight was up 7.0% (817 gallons to 874) and passengers per flight were up 13.4% (103 to 117). The distance flown was about the same (391 miles then, 391 now).

Southwest Airlines led in both years, with 32% of passengers in 2019 and 34% in 2025. United Airlines gained the most share, 5% to 20%. SkyWest Airlines lost the most, 19% to 9%. Republic Airways and Compass Airlines no longer reach 1% of passengers, having had 6% in 2019.

Airline by airline, Frontier Airlines went from 55 kg to 52 kg per passenger (191 seats per flight to 210, main aircraft Airbus A320neo in both years); SkyWest Airlines went from 101 kg to 112 kg per passenger (69 seats per flight to 70, main aircraft Embraer 175 in both years).

Denver to Salt Lake City, 2019 and 2025
Measure20192025
Passengers (thousands)1,5411,842
Flights (thousands)14.915.7
Seats filled86%80%
Gallons of fuel per flight817874
kg CO2 per passenger7773
CO2 per passenger by airline, 2019 and 2025, Denver to Salt Lake CityBar chart of kilograms of CO2 per passenger on Denver to Salt Lake City for each major airline in 2019 and in 2025.020406080Southwest Airlines 201969 kgSouthwest Airlines 202567 kgUnited Airlines 201975 kgUnited Airlines 202571 kgDelta Air Lines 201978 kgDelta Air Lines 202585 kgFrontier Airlines 201955 kgFrontier Airlines 202552 kg
CO2 per passenger by airline, 2019 and 2025, Denver to Salt Lake CityBar chart of kilograms of CO2 per passenger on Denver to Salt Lake City for each major airline in 2019 and in 2025.0255075Southwest Airlines 201969 kgSouthwest Airlines 202567 kgUnited Airlines 201975 kgUnited Airlines 202571 kgDelta Air Lines 201978 kgDelta Air Lines 202585 kgFrontier Airlines 201955 kgFrontier Airlines 202552 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.

Denver to Salt Lake City and back: time in the air

The time in the air is almost the same each way: 66 minutes on average from Denver to Salt Lake City and 61 minutes back. A difference of 5 minutes is within what routing and congestion alone produce.

Time in the air by direction, 2025
DirectionAverage minutes in the airFlights
Denver to Salt Lake City65.87,812
Salt Lake City to Denver61.27,885

Fly or drive

Driving is about 457 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 136 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 87% more than the 73 kg for a passenger on the flight.

With 2 people in the car, driving comes out lower per person than the flight (68 kg each, and 34 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 180 kg per vehicle.

CO2 per person by way of travel, Denver to Salt Lake CityBar chart of kilograms of CO2 per person flying, driving or taking the train between Denver and Salt Lake City.050100Flight, average73 kgCar, driver alone136 kgCar, 2 people68 kgCar, 4 people34 kg
CO2 per person by way of travel, Denver to Salt Lake CityBar chart of kilograms of CO2 per person flying, driving or taking the train between Denver and Salt Lake City.050100Flight, average73 kgCar, driver alone136 kgCar, 2 people68 kgCar, 4 people34 kg
CO2 per person, Denver to Salt Lake City. 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 Denver130 kg CO2 per passenger over 850 milesSan Francisco to Denver136 kg CO2 per passenger over 960 milesChicago to Denver129 kg CO2 per passenger over 890 milesNew York to Denver213 kg CO2 per passenger over 1,616 milesLos Angeles to Salt Lake City106 kg CO2 per passenger over 583 milesSan Francisco to Portland103 kg CO2 per passenger over 554 milesAtlanta to Washington, DC104 kg CO2 per passenger over 554 milesNew York to Nashville150 kg CO2 per passenger over 761 miles

Airports on this route: Denver 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.