Chicago to Atlanta

Between Chicago and Atlanta, 2.4 million passengers flew nonstop in 2025, on 19 thousand flights of about 601 miles and 1.5 hours in the air. The average passenger accounted for about 107 kg of CO2 from the fuel burned, from 72 kg on Spirit Airlines to 167 kg on Republic Airways.

107 kgCO2 per passenger, average
601 milesabout 1.5 hours in the air
2.4 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.

Chicago to Atlanta by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
Delta Air Lines	44%	7.9	Boeing 737-900ER	158	84%	110
Southwest Airlines	16%	3.2	Boeing 737-700, Boeing 737 MAX 8	162	75%	100
Frontier Airlines	15%	2.2	Airbus A320neo, Airbus A321neo	197	82%	76
United Airlines	14%	3.0	Boeing 737-700, Airbus A319	145	78%	121
American Airlines	5%	1.1	Airbus A319, Boeing 737-800	136	76%	140
Envoy Air	2%	0.7	Embraer 175	75	85%	159
Spirit Airlines	2%	0.2	Airbus A321neo, Airbus A321	209	90%	72
Republic Airways	2%	0.7	Embraer 175	76	80%	167

What explains the differences

It's number 48 of the 100 busiest city pairs by passengers, and number 76 for the lowest CO2 per mile flown (0.18 kg per passenger-mile, number 1 being the lowest). A typical route of 601 miles in this set comes out at about 102 kg, so this one is 4.8% above it.

The flights use more than one pair of airports: ATL to ORD (65%), ATL to MDW (35%). The figures here cover all of them.

The airlines on this route differ by 132% per passenger. Spirit Airlines burned 1,381 gallons per flight and 187 passengers on each, and Republic Airways 1,039 gallons and 61 passengers. The gap comes from how many passengers share each flight, not from fuel burned per flight. Spirit Airlines flew 90% full here against 80% for Republic Airways, flying mostly Airbus A321neo against Embraer 175.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 78 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 38% higher.

2019 compared with 2025

In 2019 the route carried 2.6 million passengers on 24 thousand flights. In 2025 it carried 2.4 million, down 9%, on 19 thousand flights, down 21%. The average flight had 127 seats then and 154 now, and 86% of them were filled against 81%.

CO2 per passenger was 122 kg in 2019 and 107 kg in 2025, down 11.8%. Fuel burned per flight was up 1.2% (1,361 gallons to 1,377) and passengers per flight were up 14.8% (109 to 125). The distance flown was about the same (601 miles then, 601 now).

Delta Air Lines led in both years, with 50% of passengers in 2019 and 44% in 2025. United Airlines gained the most share, 4% to 14%. American Airlines lost the most, 12% to 5%. Frontier Airlines didn't have 1% of the passengers in 2019 and now carries 15%. SkyWest Airlines and GoJet Airlines no longer reach 1% of passengers, having had 5% in 2019.

Airline by airline, Delta Air Lines went from 133 kg to 110 kg per passenger (129 seats per flight to 158, main aircraft unlisted aircraft then and Boeing 737-900ER now); American Airlines went from 113 kg to 140 kg per passenger (152 seats per flight to 136, main aircraft Boeing 737-800 then and Airbus A319 now).

Chicago to Atlanta, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,648	2,399
Flights (thousands)	24.3	19.2
Seats filled	86%	81%
Gallons of fuel per flight	1,361	1,377
kg CO2 per passenger	122	107

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 Atlanta and back: time in the air

Flights from Atlanta to Chicago spent 94 minutes in the air on average in 2025, against 86 minutes from Chicago to Atlanta: 8 minutes longer, 9% more. The route runs mostly north to south, so the winds on the day, routing and congestion decide the difference.

At this route's average burn of about 919 gallons per flight hour, those extra minutes cost about 116 gallons per flight, which is about 0.9 gallons or 9 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 Chicago	93.7	9,581
Chicago to Atlanta	86.1	9,590

Fly or drive

Driving is about 703 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 209 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 95% more than the 107 kg for a passenger on the flight.

With 2 people in the car, driving comes out lower per person than the flight (104 kg each, and 52 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 277 kg per vehicle.

CO2 per person, Chicago to Atlanta. 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, O'Hare International Airport, 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.