The carbon footprint of traveling from point A to point B depends on distance, number of passengers, and how you get there. The answer isn't always what people expect — flying is worse per person for solo travelers, but a full car can emit less per passenger than a flight.

Emissions Per Mile: Air vs. Road

Flying: commercial aviation emits approximately 255g CO₂ per passenger-mile (economy class, including non-CO₂ warming effects). Driving a gas car solo at 30 MPG: about 290g CO₂/mile. Solo driving and flying are similar on a per-mile basis, with flying slightly better per mile for most routes. However, people fly much longer distances — a 2,000-mile flight emits 510kg CO₂/passenger vs. a 500-mile drive emitting 145kg.

How Occupancy Changes Everything

With 4 passengers in a car at 30 MPG: 290g ÷ 4 = 73g CO₂ per passenger-mile — nearly 4x less than flying. This is why the question of driving vs. flying depends heavily on how many people are traveling together. A family of 4 driving cross-country emits significantly less per person than flying.

When Flying Is Lower Carbon Than Driving

For a solo traveler driving a gas SUV (20 MPG), flying economy can actually emit less CO₂ per mile. Also, trains and buses have lower emissions than both options — Amtrak averages about 150g CO₂/passenger-mile, intercity buses around 45g CO₂/passenger-mile.

Carbon by Trip Example: New York to Chicago (~790 miles)

  • Flying (solo): ~200kg CO₂
  • Driving solo (30 MPG): ~230kg CO₂
  • Driving (4 people): ~57kg CO₂ per person
  • Train: ~120kg CO₂
  • Bus: ~35kg CO₂

Use our Flight Carbon Calculator to calculate your specific route.