San Francisco International Airport (SFO)
San Francisco International Airport (SFO) carries at least 5% of the passengers on 11 of the 100 busiest US routes. On those routes about 21.1 million passengers flew through it in 2025, counting each route's airport split.
CO2 on the routes through SFO
The routes through SFO run from 71 kg of CO2 per passenger (San Francisco to Las Vegas) to 414 kg (New York to San Francisco), with a middle of 119 kg.
Every route that uses SFO, busiest first
| Route | Flown with | Share through SFO | kg CO2 per passenger |
|---|---|---|---|
| Los Angeles to San Francisco | LAX (30%), SNA (10%), BUR (6%) | 46% | 75 |
| New York to San Francisco | JFK (52%), EWR (48%) | 100% | 414 |
| Chicago to San Francisco | ORD (82%), MDW (4%) | 86% | 235 |
| San Francisco to Denver | DEN (61%) | 61% | 136 |
| San Francisco to San Diego | SAN (48%) | 48% | 78 |
| San Francisco to Las Vegas | LAS (44%) | 44% | 71 |
| San Francisco to Seattle | SEA (52%) | 52% | 119 |
| Dallas-Fort Worth to San Francisco | DFW (65%) | 65% | 193 |
| San Francisco to Phoenix | PHX (51%) | 51% | 107 |
| San Francisco to Honolulu | HNL (67%) | 67% | 300 |
| San Francisco to Portland | PDX (52%) | 52% | 103 |
Airport references
Source: US Bureau of Transportation Statistics (BTS), T-100 traffic and Schedule T-2 fuel filings; US EPA jet-fuel CO2 factor. Route calculation method.
Airlines on these routes
By passengers on the routes above, the largest are United Airlines, Southwest Airlines, American Airlines, Alaska Airlines, SkyWest Airlines and Delta Air Lines.
About these figures. The CO2 per passenger is for the whole city pair, so it covers every airport the route uses. The airline filings the figures come from don't split fuel by airport, so we can't say how a flight from SFO compares with one from a neighbouring airport. The share column is the part of the route's passengers that flew through SFO, from the same filings. How the figures are built.