Los Angeles to Houston

Between Los Angeles and Houston, 2.7 million passengers flew nonstop in 2025, on 19 thousand flights of about 1,373 miles and 2.9 hours in the air. The average passenger accounted for about 183 kg of CO2 from the fuel burned, from 140 kg on Frontier Airlines to 300 kg on SkyWest Airlines.

183 kgCO2 per passenger, average
1,373 milesabout 2.9 hours in the air
2.7 millionpassengers in 2025
84%of seats filled

CO2 per passenger, airline by airline

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

Los Angeles to Houston by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
United Airlines	53%	9.5	Boeing 737-900ER, Boeing 737 MAX 9	174	86%	181
Southwest Airlines	24%	4.9	Boeing 737 MAX 8, Boeing 737-700	164	80%	185
Spirit Airlines	9%	1.4	Airbus A320-200, Airbus A320neo	185	89%	152
Frontier Airlines	7%	1.0	Airbus A320neo, Airbus A321neo	213	84%	140
Delta Air Lines	5%	1.3	Airbus A319, Airbus A320-200	132	82%	251
SkyWest Airlines	2%	0.8	Embraer 175	76	81%	300

What explains the differences

It's number 34 of the 100 busiest city pairs by passengers, and number 19 for the lowest CO2 per mile flown (0.13 kg per passenger-mile, number 1 being the lowest). A typical route of 1,373 miles in this set comes out at about 197 kg, so this one is 7.4% below it.

The flights use more than one pair of airports: IAH to LAX (60%), HOU to LAX (13%), IAH to SNA (11%). The figures here cover all of them.

The airlines on this route differ by 114% per passenger. Frontier Airlines burned 2,571 gallons per flight and 179 passengers on each, and SkyWest Airlines 1,897 gallons and 62 passengers. The gap comes from how many passengers share each flight, not from fuel burned per flight. Frontier Airlines flew 84% full here against 81% 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 177 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 3.2% higher.

2019 compared with 2025

In 2019 the route carried 2.7 million passengers on 18 thousand flights. In 2025 it carried 2.7 million, up 1%, on 19 thousand flights, up 8%. The average flight had 171 seats then and 167 now, and 88% of them were filled against 84%.

CO2 per passenger was 192 kg in 2019 and 183 kg in 2025, down 4.9%. Fuel burned per flight was down 10.9% (2,975 gallons to 2,650) and passengers per flight were down 6.4% (151 to 141). The distance flown was about the same (1,375 miles then, 1,373 now).

United Airlines led in both years, with 56% of passengers in 2019 and 53% in 2025. United Airlines lost the most, 56% to 53%. Frontier Airlines and Delta Air Lines and SkyWest Airlines didn't have 1% of the passengers in 2019 and now together carry 14%. American Airlines and Compass Airlines no longer reach 1% of passengers, having had 8% in 2019.

Airline by airline, Spirit Airlines went from 163 kg to 152 kg per passenger (212 seats per flight to 185, main aircraft Airbus A321 then and Airbus A320-200 now); Southwest Airlines went from 184 kg to 185 kg per passenger (155 seats per flight to 164, main aircraft Boeing 737-700 then and Boeing 737 MAX 8 now).

Los Angeles to Houston, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,657	2,680
Flights (thousands)	17.6	19.0
Seats filled	88%	84%
Gallons of fuel per flight	2,975	2,650
kg CO2 per passenger	192	183

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 Houston and back: time in the air

Flights from Houston to Los Angeles spent 186 minutes in the air on average in 2025, against 166 minutes from Los Angeles to Houston: 20 minutes longer, 12% 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 903 gallons per flight hour, those extra minutes cost about 303 gallons per flight, which is about 2.1 gallons or 21 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
Houston to Los Angeles	186.0	9,493
Los Angeles to Houston	165.9	9,464

Fly or drive

Driving is about 1,606 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 477 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 161% more than the 183 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (159 kg each, and 119 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 633 kg per vehicle.

CO2 per person, Los Angeles 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: George Bush Intercontinental Airport, Los Angeles International Airport, William P. Hobby Airport, John Wayne Airport, Ontario 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.