Atlanta to Houston

Between Atlanta and Houston, 2.1 million passengers flew nonstop in 2025, on 16 thousand flights of about 692 miles and 1.6 hours in the air. The average passenger accounted for about 116 kg of CO2 from the fuel burned, from 80 kg on Frontier Airlines to 154 kg on Mesa Airlines.

116 kgCO2 per passenger, average
692 milesabout 1.6 hours in the air
2.1 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.

Atlanta to Houston by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
Delta Air Lines	49%	7.6	Airbus A321, Airbus A320-200	159	83%	123
Southwest Airlines	18%	3.1	Boeing 737 MAX 8, Boeing 737-700	164	74%	113
United Airlines	10%	1.9	Airbus A320-200, Airbus A319	146	77%	131
Frontier Airlines	10%	1.2	Airbus A320neo, Airbus A321neo	209	84%	80
Spirit Airlines	9%	1.1	Airbus A320-200, Airbus A321neo	195	84%	87
Mesa Airlines	4%	1.3	Embraer 175	74	85%	154

What explains the differences

It's number 64 of the 100 busiest city pairs by passengers, and number 69 for the lowest CO2 per mile flown (0.17 kg per passenger-mile, number 1 being the lowest). A typical route of 692 miles in this set comes out at about 114 kg, so this one is close to that.

The flights use more than one pair of airports: ATL to IAH (67%), ATL to HOU (33%). The figures here cover all of them.

The airlines on this route differ by 92% per passenger. Frontier Airlines burned 1,436 gallons per flight and 175 passengers on each, and Mesa Airlines 992 gallons and 63 passengers. The gap comes from how many passengers share each flight, not from fuel burned per flight. Frontier Airlines flew 84% full here against 85% for Mesa 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 89 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 30% higher.

2019 compared with 2025

In 2019 the route carried 2.1 million passengers on 19 thousand flights. In 2025 it carried 2.1 million, up 0%, on 16 thousand flights, down 14%. The average flight had 130 seats then and 158 now, and 84% of them were filled against 81%.

CO2 per passenger was 133 kg in 2019 and 116 kg in 2025, down 13.1%. Fuel burned per flight was up 1.5% (1,497 gallons to 1,520) and passengers per flight were up 16.7% (110 to 128). The distance flown was about the same (692 miles then, 692 now).

Delta Air Lines led in both years, with 55% of passengers in 2019 and 49% in 2025. Delta Air Lines lost the most, 55% to 49%. United Airlines and Frontier Airlines didn't have 1% of the passengers in 2019 and now together carry 20%. Republic Airways and ExpressJet and SkyWest Airlines no longer reach 1% of passengers, having had 7% in 2019.

Airline by airline, Delta Air Lines went from 142 kg to 123 kg per passenger (139 seats per flight to 159, main aircraft unlisted aircraft then and Airbus A321 now); Southwest Airlines went from 113 kg to 113 kg per passenger (152 seats per flight to 164, main aircraft Boeing 737-700 then and Boeing 737 MAX 8 now).

The airports changed too: ATL to IAH handled 56% of the passengers in 2019 and 67% in 2025.

Atlanta to Houston, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,055	2,064
Flights (thousands)	18.7	16.1
Seats filled	84%	81%
Gallons of fuel per flight	1,497	1,520
kg CO2 per passenger	133	116

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.

Atlanta to Houston and back: time in the air

Flights from Atlanta to Houston spent 105 minutes in the air on average in 2025, against 93 minutes from Houston to Atlanta: 13 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 921 gallons per flight hour, those extra minutes cost about 192 gallons per flight, which is about 1.5 gallons or 15 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
Atlanta to Houston	105.2	8,079
Houston to Atlanta	92.7	8,042

Fly or drive

Driving is about 810 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 240 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 108% more than the 116 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (80 kg each, and 60 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 319 kg per vehicle.

CO2 per person, Atlanta to Houston. 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: Hartsfield-Jackson Atlanta International Airport, George Bush Intercontinental Airport, William P. Hobby 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.