Dallas-Fort Worth to Denver

Between Dallas-Fort Worth and Denver, 2.5 million passengers flew nonstop in 2025, on 18 thousand flights of about 644 miles and 1.6 hours in the air. The average passenger accounted for about 102 kg of CO2 from the fuel burned, from 77 kg on Frontier Airlines to 116 kg on United Airlines.

102 kgCO2 per passenger, average
644 milesabout 1.6 hours in the air
2.5 millionpassengers in 2025
81%of seats filled

CO2 per passenger, airline by airline

Kilograms of CO2 per passenger, one way, 2025. Fuel burned only. Less is better.

Dallas-Fort Worth to Denver by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
American Airlines	37%	5.9	Airbus A321, Boeing 737-800	187	85%	103
Southwest Airlines	30%	6.0	Boeing 737 MAX 8, Boeing 737-800	166	76%	104
United Airlines	19%	3.9	Airbus A319, Boeing 737-800	150	83%	116
Frontier Airlines	14%	2.0	Airbus A320neo, Airbus A321neo	211	82%	77

What explains the differences

It's number 44 of the 100 busiest city pairs by passengers, and number 58 for the lowest CO2 per mile flown (0.16 kg per passenger-mile, number 1 being the lowest). A typical route of 644 miles in this set comes out at about 108 kg, so this one is 4.9% below it.

The flights use more than one pair of airports: DFW to DEN (70%), DAL to DEN (30%). The figures here cover all of them.

The airlines on this route differ by 50% per passenger. Frontier Airlines burned 1,371 gallons per flight and 173 passengers on each, and United Airlines 1,472 gallons and 124 passengers. Fuel burned per flight explains about 17% of the gap and the number of passengers on each flight the other 83%. Frontier Airlines flew 82% full here against 83% for United Airlines, flying mostly Airbus A320neo against Airbus A319.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 83 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 23% higher.

2019 compared with 2025

In 2019 the route carried 2.3 million passengers on 17 thousand flights. In 2025 it carried 2.5 million, up 8%, on 18 thousand flights, up 6%. The average flight had 158 seats then and 174 now, and 88% of them were filled against 81%.

CO2 per passenger was 102 kg in 2019 and 102 kg in 2025, unchanged. Fuel burned per flight was up 2.4% (1,449 gallons to 1,484) and passengers per flight were up 2.1% (138 to 141). The distance flown was about the same (644 miles then, 644 now).

American Airlines led in both years, with 43% of passengers in 2019 and 37% in 2025. United Airlines gained the most share, 11% to 19%. American Airlines lost the most, 43% to 37%. Spirit Airlines and SkyWest Airlines no longer reach 1% of passengers, having had 7% in 2019.

Airline by airline, Frontier Airlines went from 79 kg to 77 kg per passenger (179 seats per flight to 211, main aircraft Airbus A320neo in both years); United Airlines went from 110 kg to 116 kg per passenger (150 seats per flight to 150, main aircraft Airbus A319 in both years).

Dallas-Fort Worth to Denver, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,335	2,519
Flights (thousands)	16.9	17.8
Seats filled	88%	81%
Gallons of fuel per flight	1,449	1,484
kg CO2 per passenger	102	102

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.

Dallas-Fort Worth to Denver and back: time in the air

Flights from Dallas-Fort Worth to Denver spent 99 minutes in the air on average in 2025, against 89 minutes from Denver to Dallas-Fort Worth: 10 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 944 gallons per flight hour, those extra minutes cost about 154 gallons per flight, which is about 1.1 gallons or 11 kg of CO2 for each passenger on the slower direction. The route figure above averages both directions.

Time in the air by direction, 2025

Direction	Average minutes in the air	Flights
Dallas-Fort Worth to Denver	99.2	8,898
Denver to Dallas-Fort Worth	89.4	8,940

Fly or drive

Driving is about 753 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 224 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 118% more than the 102 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (75 kg each, and 56 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 297 kg per vehicle.

CO2 per person, Dallas-Fort Worth to Denver. 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

Airports on this route: Dallas/Fort Worth International Airport, Denver International Airport, Dallas Love Field.

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.