Quick Answer — How Much CO2 Does a Flight Produce?
A flight's carbon footprint is roughly distance × an emissions factor per mile × a cabin-class multiplier, and the per-mile factor itself is not constant — short flights pollute more per mile flown than long ones, because take-off and climb are the most fuel-intensive part of any trip and a short-haul flight spends a bigger share of its journey in that phase.
The baseline formula (economy class): short-haul flights (under about 2,300 miles) use 0.2024 kg CO2e per mile, while long-haul flights use 0.1884 kg CO2e per mile. Both figures come from DEFRA's 2026 conversion factors and already include radiative forcing — the extra warming effect of contrails and high-altitude nitrogen oxides, which a plain fuel-burn number leaves out.
Quick reference (one economy passenger, one-way):
- 500 mi (e.g. NYC–Chicago) → 101 kg CO2e (0.10 t)
- 1,200 mi (e.g. NYC–Denver) → 243 kg CO2e (0.24 t)
- 2,500 mi (e.g. NYC–LA) → 471 kg CO2e (0.47 t)
- 4,500 mi (e.g. NYC–London) → 848 kg CO2e (0.85 t)
- 7,500 mi (e.g. NYC–Tokyo) → 1,413 kg CO2e (1.41 t)
Round trips simply double the one-way figure, and business or first class multiply it further — see the cabin-class section below before you assume economy math applies to your seat.