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Rankings / Routes / Miami to Houston

2025 flights

Miami to Houston

Between Miami and Houston, 2.0 million passengers flew nonstop in 2025, on 15 thousand flights of about 964 miles and 2.2 hours in the air. The average passenger accounted for about 142 kg of CO2 from the fuel burned, from 115 kg on Spirit Airlines to 161 kg on American Airlines.

  • 142 kgCO2 per passenger, average
  • 964 milesabout 2.2 hours in the air
  • 2.0 millionpassengers in 2025
  • 77%of seats filled

CO2 per passenger, airline by airline

CO2 per passenger by airline, Miami to HoustonBar chart of kilograms of CO2 per passenger on each airline between Miami and Houston in 2025.050100150Spirit Airlines115 kgFrontier Airlines131 kgSouthwest Airlines132 kgUnited Airlines153 kgAmerican Airlines161 kg
CO2 per passenger by airline, Miami to HoustonBar chart of kilograms of CO2 per passenger on each airline between Miami and Houston in 2025.050100150Spirit Airlines115 kgFrontier Airlines131 kgSouthwest Airlines132 kgUnited Airlines153 kgAmerican Airlines161 kg
Kilograms of CO2 per passenger, one way, 2025. Fuel burned only. Less is better.
Miami to Houston by airline, 2025
AirlineShare of passengersFlights (thousands)Main aircraftSeats per flightSeats filledkg CO2 per passenger
United Airlines38%6.1Boeing 737-800, Boeing 737 MAX 817175%153
Spirit Airlines26%3.3Airbus A321neo, Airbus A320neo20380%115
American Airlines18%2.9Boeing 737-800, Boeing 737 MAX 816477%161
Southwest Airlines14%2.2Boeing 737 MAX 8, Boeing 737-80016780%132
Frontier Airlines2%0.3Airbus A320neo, Airbus A321neo20769%131

What explains the differences

It's number 67 of the 100 busiest city pairs by passengers, and number 41 for the lowest CO2 per mile flown (0.15 kg per passenger-mile, number 1 being the lowest). A typical route of 964 miles in this set comes out at about 147 kg, so this one is 3.7% below it.

The flights use more than one pair of airports: IAH to MIA (48%), IAH to FLL (38%), HOU to FLL (11%). The figures here cover all of them.

The airlines on this route differ by 39% per passenger. Spirit Airlines burned 1,921 gallons per flight and 162 passengers on each, and American Airlines 2,081 gallons and 126 passengers. Fuel burned per flight explains about 24% of the gap and the number of passengers on each flight the other 76%. Spirit Airlines flew 80% full here against 77% for American Airlines, flying mostly Airbus A321neo against Boeing 737-800.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 124 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 14% higher.

2019 compared with 2025

In 2019 the route carried 1.7 million passengers on 13 thousand flights. In 2025 it carried 2.0 million, up 18%, on 15 thousand flights, up 15%. The average flight had 152 seats then and 175 now, and 86% of them were filled against 77%.

CO2 per passenger was 150 kg in 2019 and 142 kg in 2025, down 5.6%. Fuel burned per flight was down 2.7% (2,011 gallons to 1,958) and passengers per flight were up 3.1% (131 to 135). The distance flown was about the same (963 miles then, 964 now).

United Airlines led in both years, with 49% of passengers in 2019 and 38% in 2025. Spirit Airlines gained the most share, 9% to 26%. United Airlines lost the most, 49% to 38%. Frontier Airlines didn't have 1% of the passengers in 2019 and now carries 2%. Republic Airways no longer reaches 1% of passengers, having had 4% in 2019.

Airline by airline, Spirit Airlines went from 139 kg to 115 kg per passenger (179 seats per flight to 203, main aircraft Airbus A319 then and Airbus A321neo now); United Airlines went from 146 kg to 153 kg per passenger (160 seats per flight to 171, main aircraft Airbus A320-200 then and Boeing 737-800 now).

Miami to Houston, 2019 and 2025
Measure20192025
Passengers (thousands)1,7102,025
Flights (thousands)13.115.0
Seats filled86%77%
Gallons of fuel per flight2,0111,958
kg CO2 per passenger150142
CO2 per passenger by airline, 2019 and 2025, Miami to HoustonBar chart of kilograms of CO2 per passenger on Miami to Houston for each major airline in 2019 and in 2025.050100150United Airlines 2019146 kgUnited Airlines 2025153 kgSpirit Airlines 2019139 kgSpirit Airlines 2025115 kgAmerican Airlines 2019162 kgAmerican Airlines 2025161 kgSouthwest Airlines 2019138 kgSouthwest Airlines 2025132 kg
CO2 per passenger by airline, 2019 and 2025, Miami to HoustonBar chart of kilograms of CO2 per passenger on Miami to Houston for each major airline in 2019 and in 2025.050100150United Airlines 2019146 kgUnited Airlines 2025153 kgSpirit Airlines 2019139 kgSpirit Airlines 2025115 kgAmerican Airlines 2019162 kgAmerican Airlines 2025161 kgSouthwest Airlines 2019138 kgSouthwest Airlines 2025132 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.

Miami to Houston and back: time in the air

Flights from Miami to Houston spent 140 minutes in the air on average in 2025, against 120 minutes from Houston to Miami: 20 minutes longer, 16% 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 296 gallons per flight, which is about 2.2 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
DirectionAverage minutes in the airFlights
Miami to Houston140.07,527
Houston to Miami120.37,503

Fly or drive

Driving is about 1,128 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 335 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 137% more than the 142 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (112 kg each, and 84 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 444 kg per vehicle.

CO2 per person by way of travel, Miami to HoustonBar chart of kilograms of CO2 per person flying, driving or taking the train between Miami and Houston.0100200300Flight, average142 kgCar, driver alone335 kgCar, 2 people167 kgCar, 4 people84 kg
CO2 per person by way of travel, Miami to HoustonBar chart of kilograms of CO2 per person flying, driving or taking the train between Miami and Houston.0100200300Flight, average142 kgCar, driver alone335 kgCar, 2 people167 kgCar, 4 people84 kg
CO2 per person, Miami 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

New York to Miami158 kg CO2 per passenger over 1,082 milesAtlanta to Miami96 kg CO2 per passenger over 587 milesMiami to Washington, DC144 kg CO2 per passenger over 921 milesChicago to Miami161 kg CO2 per passenger over 1,187 milesNew York to Dallas-Fort Worth203 kg CO2 per passenger over 1,384 milesOrlando to Boston163 kg CO2 per passenger over 1,111 milesLas Vegas to Seattle128 kg CO2 per passenger over 867 miles

Airports on this route: George Bush Intercontinental Airport, Miami International Airport, Fort Lauderdale-Hollywood, 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.