Chicago to Miami

Between Chicago and Miami, 2.7 million passengers flew nonstop in 2025, on 18 thousand flights of about 1,187 miles and 2.7 hours in the air. The average passenger accounted for about 161 kg of CO2 from the fuel burned, from 133 kg on Spirit Airlines to 171 kg on American Airlines.

161 kgCO2 per passenger, average
1,187 milesabout 2.7 hours in the air
2.7 millionpassengers in 2025
83%of seats filled

CO2 per passenger, airline by airline

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

Chicago to Miami by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
American Airlines	40%	7.3	Boeing 737-800, Boeing 737 MAX 8	173	86%	171
United Airlines	25%	4.5	Airbus A321neo, Boeing 737-800	189	80%	167
Spirit Airlines	18%	2.7	Airbus A321neo, Airbus A321	211	84%	133
Southwest Airlines	16%	3.2	Boeing 737 MAX 8, Boeing 737-700	165	81%	161
Frontier Airlines	1%	0.2	Airbus A320neo, Airbus A321neo	189	76%	152

What explains the differences

It's number 32 of the 100 busiest city pairs by passengers, and number 22 for the lowest CO2 per mile flown (0.14 kg per passenger-mile, number 1 being the lowest). A typical route of 1,187 miles in this set comes out at about 174 kg, so this one is 7.5% below it.

The flights use more than one pair of airports: ORD to MIA (48%), ORD to FLL (35%), MDW to FLL (11%). The figures here cover all of them.

The airlines on this route differ by 29% per passenger. Spirit Airlines burned 2,414 gallons per flight and 177 passengers on each, and American Airlines 2,592 gallons and 148 passengers. Fuel burned per flight explains about 28% of the gap and the number of passengers on each flight the other 72%. Spirit Airlines flew 84% full here against 86% 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 153 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 5.3% higher.

2019 compared with 2025

In 2019 the route carried 2.4 million passengers on 16 thousand flights. In 2025 it carried 2.7 million, up 10%, on 18 thousand flights, up 13%. The average flight had 171 seats then and 181 now, and 90% of them were filled against 83%.

CO2 per passenger was 166 kg in 2019 and 161 kg in 2025, down 2.8%. Fuel burned per flight was down 4.8% (2,624 gallons to 2,498) and passengers per flight were down 2.0% (154 to 151). The distance flown was about the same (1,187 miles then, 1,187 now).

American Airlines led in both years, with 46% of passengers in 2019 and 40% in 2025. Spirit Airlines gained the most share, 11% to 18%. American Airlines lost the most, 46% to 40%. JetBlue no longer reaches 1% of passengers, having had 4% in 2019.

Airline by airline, Spirit Airlines went from 142 kg to 133 kg per passenger (203 seats per flight to 211, main aircraft Airbus A321 then and Airbus A321neo now); Southwest Airlines went from 156 kg to 161 kg per passenger (160 seats per flight to 165, main aircraft Boeing 737-800 then and Boeing 737 MAX 8 now).

Chicago to Miami, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,444	2,695
Flights (thousands)	15.9	17.9
Seats filled	90%	83%
Gallons of fuel per flight	2,624	2,498
kg CO2 per passenger	166	161

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.

Chicago to Miami and back: time in the air

Flights from Miami to Chicago spent 166 minutes in the air on average in 2025, against 154 minutes from Chicago to Miami: 12 minutes longer, 8% 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 934 gallons per flight hour, those extra minutes cost about 188 gallons per flight, which is about 1.2 gallons or 12 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
Miami to Chicago	166.4	8,911
Chicago to Miami	154.3	8,939

Fly or drive

Driving is about 1,389 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 412 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 156% more than the 161 kg for a passenger on the flight.

With 3 people in the car, driving comes out lower per person than the flight (137 kg each, and 103 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 547 kg per vehicle.

CO2 per person, Chicago to Miami. 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: O'Hare International Airport, Miami International Airport, Fort Lauderdale-Hollywood, Midway 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.