Love the middle seat
The more people on any particular aircraft the more efficient that aircraft becomes per passenger. On a packed aircraft the significant emissions of simply getting the aircraft aloft gets split between many people and the per passenger emissions drop significantly. This is a rare instance where an airline's incentives align with the environment.
There are a number of ways more people can be put on an aircraft
- Use economy seats rather than higher class seats because they take less room.
- Use a budget airline which fits more seats into an aircraft than a legacy airline.
- Choose a fully booked flight which by definition is carrying more people.
So while sitting in the middle economy seat on a budget airline might not be ideal for your personal comfort, it's good for the environment.
The Travelyst impact model used by Google Flights and mentioned on the Action page estimates emissions using the above factors. It estimates the contributions from seating layout and then additionally uses historical data on flight loading.
The scenario below presents a significant contrast between an individual flying first class SFO to BOS on a lightly booked aircraft and an individual flying the same route in economy on a fully packed budget airline. The avoided emissions are very significant.