It was hard to find emissions data on the Rotax 912, from a Rotax support list [1]:

>> I am looking for emissions data for the 912 iSc powerplant. I am in need of data regarding VOC and NO emissions.

> I suspect you will have to measure this yourself. I cannot think of a reason why any user outside Rotax would know this, but good luck.

even harder to find emissions on an unknown road vehicle. Lead for autos was phased out in the US starting in the 1980s. I stopped using leaded gas my 1972 VW Beetle (designed to run leaded) in the late 80s. I know some piston A/C are running unleaded, but it is glacial progress compared to cars. Having been in the industry, I am well aware of the reasons (certification/safety requirements, politics and lobbyists). I just regret in my ignorance at the time I contributed to the problem.

(I would also assume you and your parents live next to airstrips, eliminating the need to get to one.)

I think our problem is more systemic. A better question than "Do I fly or drive?" might be "Why don't I live closer to my extended family and friends?"

In fact the computer industry uses more energy than the aviation industry [2]--cryptocurrency and AI are just going to add to it. When I design software, I try to keep efficiency and utility in mind--but the human mind is good at rationalizing what it needs to. Who needs software used to repair broken tech? Hopefully more people than need single engine aircraft or jets.

[1] https://www.rotax-owner.com/en/912is-technical-questions/653...

[2] https://dl.acm.org/doi/pdf/10.1145/3483410