San Francisco to Honolulu

Between San Francisco and Honolulu, 1.8 million passengers flew nonstop in 2025, on 8 thousand flights of about 2,404 miles and 4.8 hours in the air. The average passenger accounted for about 300 kg of CO2 from the fuel burned, from 237 kg on Southwest Airlines to 334 kg on United Airlines.

300 kgCO2 per passenger, average
2,404 milesabout 4.8 hours in the air
1.8 millionpassengers in 2025
90%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 Honolulu by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
United Airlines	51%	3.3	Boeing 777-200, Boeing 737 MAX 9	292	91%	334
Hawaiian Airlines	30%	2.6	Airbus A321neo, Airbus A330-200	221	90%	278
Southwest Airlines	17%	1.8	Boeing 737 MAX 8, Boeing 737-800	175	92%	237
Alaska Airlines	3%	0.3	Boeing 737 MAX 9, Boeing 737-900ER	177	79%	289

What explains the differences

It's number 85 of the 100 busiest city pairs by passengers, and number 2 for the lowest CO2 per mile flown (0.12 kg per passenger-mile, number 1 being the lowest). A typical route of 2,404 miles in this set comes out at about 324 kg, so this one is 7.4% below it.

The flights use more than one pair of airports: HNL to SFO (67%), HNL to SJC (17%), HNL to OAK (16%). The figures here cover all of them.

The airlines on this route differ by 41% per passenger. Southwest Airlines burned 3,907 gallons per flight and 161 passengers on each, and United Airlines 9,093 gallons and 265 passengers. The gap comes from fuel burned per flight, a little of it offset by passengers per flight. Southwest Airlines flew 92% full here against 91% for United Airlines, flying mostly Boeing 737 MAX 8 against Boeing 777-200.

For comparison, the EPA default factor for a flight of this length (0.163 kg per passenger-mile) would give 392 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 23% lower.

2019 compared with 2025

In 2019 the route carried 1.9 million passengers on 9 thousand flights. In 2025 it carried 1.8 million, down 6%, on 8 thousand flights, down 12%. The average flight had 231 seats then and 238 now, and 87% of them were filled against 90%.

CO2 per passenger was 310 kg in 2019 and 300 kg in 2025, down 3.3%. Fuel burned per flight was up 3.0% (6,426 gallons to 6,621) and passengers per flight were up 6.6% (202 to 215). The distance flown was about the same (2,404 miles then, 2,404 now).

United Airlines led in both years, with 48% of passengers in 2019 and 51% in 2025. Hawaiian Airlines gained the most share, 25% to 30%. Alaska Airlines lost the most, 13% to 3%.

Airline by airline, Southwest Airlines went from 262 kg to 237 kg per passenger (175 seats per flight to 175, main aircraft Boeing 737-800 then and Boeing 737 MAX 8 now); United Airlines went from 338 kg to 334 kg per passenger (291 seats per flight to 292, main aircraft Boeing 777-200 in both years).

San Francisco to Honolulu, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	1,874	1,755
Flights (thousands)	9.3	8.2
Seats filled	87%	90%
Gallons of fuel per flight	6,426	6,621
kg CO2 per passenger	310	300

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 Honolulu and back: time in the air

Flights from San Francisco to Honolulu spent 300 minutes in the air on average in 2025, against 278 minutes from Honolulu to San Francisco: 22 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 1,374 gallons per flight hour, those extra minutes cost about 511 gallons per flight, which is about 2.4 gallons or 23 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
San Francisco to Honolulu	300.4	4,083
Honolulu to San Francisco	278.1	4,073

Fly or drive

There's no road between San Francisco and Honolulu, so the choice is a flight or a boat, and a flight is the only practical option for most trips.

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 Orlando to San Juan138 kg CO2 per passenger over 1,189 miles Los Angeles to Miami292 kg CO2 per passenger over 2,342 miles Los Angeles to Honolulu321 kg CO2 per passenger over 2,560 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.