San Francisco to Portland

Between San Francisco and Portland, 1.7 million passengers flew nonstop in 2025, on 17 thousand flights of about 554 miles and 1.4 hours in the air. The average passenger accounted for about 103 kg of CO2 from the fuel burned, from 86 kg on Alaska Airlines to 138 kg on SkyWest Airlines.

103 kgCO2 per passenger, average
554 milesabout 1.4 hours in the air
1.7 millionpassengers in 2025
78%of seats filled

CO2 per passenger, airline by airline

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

San Francisco to Portland by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
Southwest Airlines	32%	4.8	Boeing 737-700, Boeing 737 MAX 8	162	72%	97
United Airlines	25%	3.4	Airbus A320-200, Boeing 737-800	159	81%	94
Alaska Airlines	20%	2.5	Boeing 737-900ER, Boeing 737 MAX 9	172	80%	86
Horizon Air	14%	3.9	Embraer 175	76	81%	138
SkyWest Airlines	8%	2.3	Embraer 175	75	85%	138

What explains the differences

It's number 86 of the 100 busiest city pairs by passengers, and number 80 for the lowest CO2 per mile flown (0.19 kg per passenger-mile, number 1 being the lowest). A typical route of 554 miles in this set comes out at about 97 kg, so this one is 6.3% above it.

The flights use more than one pair of airports: SFO to PDX (52%), SJC to PDX (25%), OAK to PDX (23%). The figures here cover all of them.

The airlines on this route differ by 60% per passenger. Alaska Airlines burned 1,211 gallons per flight and 137 passengers on each, and SkyWest Airlines 898 gallons and 64 passengers. The gap comes from how many passengers share each flight, not from fuel burned per flight. Alaska Airlines flew 80% full here against 85% for SkyWest Airlines, flying mostly Boeing 737-900ER against Embraer 175.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 71 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 44% higher.

2019 compared with 2025

In 2019 the route carried 2.7 million passengers on 25 thousand flights. In 2025 it carried 1.7 million, down 35%, on 17 thousand flights, down 31%. The average flight had 141 seats then and 132 now, and 78% of them were filled against 78%.

CO2 per passenger was 105 kg in 2019 and 103 kg in 2025, down 2.3%. Fuel burned per flight was down 8.7% (1,184 gallons to 1,081) and passengers per flight were down 6.5% (110 to 103). The distance flown was about the same (554 miles then, 554 now).

Southwest Airlines led in both years, with 34% of passengers in 2019 and 32% in 2025. Horizon Air gained the most share, 5% to 14%. Alaska Airlines lost the most, 30% to 20%. Sun Country Airlines no longer reaches 1% of passengers, having had 1% in 2019.

Airline by airline, Alaska Airlines went from 105 kg to 86 kg per passenger (157 seats per flight to 172, main aircraft Boeing 737-800 then and Boeing 737-900ER now); Horizon Air went from 131 kg to 138 kg per passenger (76 seats per flight to 76, main aircraft Embraer 175 in both years).

The airports changed too: SFO to PDX handled 48% of the passengers in 2019 and 52% in 2025.

San Francisco to Portland, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	2,705	1,748
Flights (thousands)	24.6	17.0
Seats filled	78%	78%
Gallons of fuel per flight	1,184	1,081
kg CO2 per passenger	105	103

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.

San Francisco to Portland and back: time in the air

The time in the air is almost the same each way: 82 minutes on average from San Francisco to Portland and 85 minutes back. A difference of 4 minutes is within what routing and congestion alone produce.

Time in the air by direction, 2025

Direction	Average minutes in the air	Flights
Portland to San Francisco	85.2	8,518
San Francisco to Portland	81.7	8,522

Fly or drive

Driving is about 648 miles by road, which we estimate as 1.17 times the straight-line distance. An average car emits about 193 kg of CO2 on the trip, at the EPA figure of 0.297 kg per vehicle-mile. Alone, that's 87% more than the 103 kg for a passenger on the flight.

With 2 people in the car, driving comes out lower per person than the flight (96 kg each, and 48 kg each for four). A larger SUV or pickup (0.394 kg per mile) would emit about 255 kg per vehicle.

CO2 per person, San Francisco to Portland. 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

Los Angeles to San Francisco75 kg CO2 per passenger over 337 miles San Francisco to Las Vegas71 kg CO2 per passenger over 404 miles New York to San Francisco414 kg CO2 per passenger over 2,578 miles San Francisco to San Diego78 kg CO2 per passenger over 436 miles Los Angeles to Salt Lake City106 kg CO2 per passenger over 583 miles Denver to Salt Lake City73 kg CO2 per passenger over 391 miles Atlanta to Washington, DC104 kg CO2 per passenger over 554 miles

Airports on this route: San Francisco International Airport, San Jose International Airport, Oakland San Francisco Bay 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.