New York to San Juan

Between New York and San Juan, 2.1 million passengers flew nonstop in 2025, on 13 thousand flights of about 1,603 miles and 3.5 hours in the air. The average passenger accounted for about 202 kg of CO2 from the fuel burned, from 169 kg on Frontier Airlines to 232 kg on United Airlines.

202 kgCO2 per passenger, average
1,603 milesabout 3.5 hours in the air
2.1 millionpassengers in 2025
87%of seats filled

CO2 per passenger, airline by airline

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

New York to San Juan by airline, 2025

Airline	Share of passengers	Flights (thousands)	Main aircraft	Seats per flight	Seats filled	kg CO2 per passenger
JetBlue	46%	6.5	Airbus A320-200, Airbus A321	171	87%	214
Delta Air Lines	18%	2.2	Airbus A321neo, Boeing 737-900ER	193	91%	173
Frontier Airlines	18%	2.1	Airbus A321neo, Airbus A320neo	217	84%	169
United Airlines	18%	2.2	Boeing 737 MAX 9, Boeing 767-400ER	197	87%	232

What explains the differences

It's number 61 of the 100 busiest city pairs by passengers, and number 6 for the lowest CO2 per mile flown (0.13 kg per passenger-mile, number 1 being the lowest). A typical route of 1,603 miles in this set comes out at about 226 kg, so this one is 10% below it.

The flights use more than one pair of airports: JFK to SJU (61%), EWR to SJU (35%), HPN to SJU (4%). The figures here cover all of them.

The airlines on this route differ by 37% per passenger. Frontier Airlines burned 3,147 gallons per flight and 181 passengers on each, and United Airlines 4,103 gallons and 172 passengers. Fuel burned per flight explains about 84% of the gap and the number of passengers on each flight the other 16%. Frontier Airlines flew 84% full here against 87% for United Airlines, flying mostly Airbus A321neo against Boeing 737 MAX 9.

For comparison, the EPA default factor for a flight of this length (0.129 kg per passenger-mile) would give 207 kg. The EPA figure is a national average for flights of that length. The measured figure for this route is 2.3% lower.

2019 compared with 2025

In 2019 the route carried 1.5 million passengers on 9 thousand flights. In 2025 it carried 2.1 million, up 45%, on 13 thousand flights, up 44%. The average flight had 181 seats then and 187 now, and 89% of them were filled against 87%.

CO2 per passenger was 220 kg in 2019 and 202 kg in 2025, down 8.3%. Fuel burned per flight was down 7.5% (3,630 gallons to 3,358) and passengers per flight were up 0.9% (161 to 162). The distance flown was about the same (1,601 miles then, 1,603 now).

JetBlue led in both years, with 56% of passengers in 2019 and 46% in 2025. JetBlue lost the most, 56% to 46%. Frontier Airlines didn't have 1% of the passengers in 2019 and now carries 18%.

Airline by airline, Delta Air Lines went from 202 kg to 173 kg per passenger (182 seats per flight to 193, main aircraft Boeing 737-900ER then and Airbus A321neo now); JetBlue went from 218 kg to 214 kg per passenger (173 seats per flight to 171, main aircraft Airbus A320-200 in both years).

The airports changed too: JFK to SJU handled 68% of the passengers in 2019 and 61% in 2025.

New York to San Juan, 2019 and 2025

Measure	2019	2025
Passengers (thousands)	1,458	2,119
Flights (thousands)	9.1	13.1
Seats filled	89%	87%
Gallons of fuel per flight	3,630	3,358
kg CO2 per passenger	220	202

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.

New York to San Juan and back: time in the air

Flights from San Juan to New York spent 217 minutes in the air on average in 2025, against 203 minutes from New York to San Juan: 14 minutes longer, 7% 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 960 gallons per flight hour, those extra minutes cost about 224 gallons per flight, which is about 1.4 gallons or 13 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 Juan to New York	216.9	6,528
New York to San Juan	202.9	6,543

Fly or drive

There's no road between New York and San Juan, 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

Airports on this route: John F. Kennedy International Airport, Newark Liberty 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.