The FAA regulations that it operates under probably provide a pretty good set of rules for what counts or doesn't, at least in the US:
https://en.wikipedia.org/wiki/Federal_Aviation_Regulations

Parts 23, 25, 91, 121, and 135 are the ones of interest.

I'm personally rooting for these: https://www.regentcraft.com/seagliders/viceroy

REGENT | Viceroy Seaglider

Viceroy is REGENT’s flagship seaglider – a 12 passenger variant with 160 nautical mile range with existing battery technology.

@RobertCousineau they fly above the waves at almost 200mph, but legally they are classified closer to boats than they are to planes so they can have a much larger legal flight distance (since they are legally allowed to get close to empty on their batteries in non-emergency situations). Successful 1/4 size model flight last September, planned full size next year, lots of industry investors/executives, etc.

Neom invested in them. not sure if I should sell my position.

I think commercial operation has to be defined - are we talking regular scheduled service?

just looking at energy density of the various storage options it makes absolutely no sense to have electric airplanes, but i can still see some investors burning money and making it happen

Relevant maybe ... retrofit completed testing and uk aviation authority approval already with flights in England "before the end of this year"...

https://www.canarymedia.com/articles/air-travel/the-first-hydrogen-powered-planes-are-taking-flight#:~:text=Universal%20Hydrogen%20is%20also%20preparing,year%20or%20in%20early%202026.

The first hydrogen-powered planes are taking flight

Aircraft retrofitted with hydrogen fuel cells could slash CO2 emissions from small planes — and potentially pave the way for hydrogen jets, new study…

Would this count? https://harbourair.com/earth-day-eplane-update/

Earth Day ePlane Update

Happy Earth Day! It has been quite a while since we provided an update on our electric journey, mostly because our team has been focused on navigating the ever-changing path to certification for an all-electric aircraft.  When we last posted, we had just completed our first point-to-point flight. Since that amazing day, there have been […]

Part 23 or Part 25?

@Yves And for commercial service: Part 91 (presumably not), 121, or 135?

Limit order set at 33%.

Possible! https://www.dw.com/en/are-electric-planes-ready-for-takeoff/a-64491147

@jacksonpolack Certainly! So I decided to provide a somewhat agressive cut-off year, to keep it interesting.

Distance & capacity?

@ElliotDavies Any flight one can commonly charter from a commercial airline to get from A to B. No one-off deals. I think that rules out a two-seater, but as for distance and capacity, I don't think I could provide a sensible cut-off?