MPG-wise sure. Emissions-wise almost certainly not. Airplanes don't have catalytic converters, exhaust recirculation, etc.

Does this include the emissions portal-to-portal? Airports tend to be nowhere near destinations because people don’t like living near all the pollution airplanes spew.

Most of my trips in small planes are pretty point to point. The airports I've used have been between 1 and 5 miles from my house and most of my destinations were similarly close (I just checked one destination and it was 200 meters).

Not sure where you're from but airport density in the US is incredibly high thanks to WWII and Cold War leftover infrastructure (and a fairly robust GA culture up through the 80s). People just don't notice their little local airports unless they fly.

Avgas (most commonly 100LL) continues to spew out lead, which was phased out for cars in 1996 in the US, is a major pollutant.

[1] https://www.epa.gov/newsreleases/epa-determines-lead-emissio... [2] https://www.nbcnews.com/business/business-news/leaded-gas-wa...