Turbine powered helicopters can appreciate in value if demand picks up because the tech doesn't move that quickly, as can GA aircraft that are already old because they're all cheap and rudimentary to start off with. (The supposed appreciating asset tends to cost a lot more than the asset appreciation to maintain though...)

Fixed wing commercial airliners generally don't, because airlines' biggest cost is fuel and new aircraft are a lot more efficient than older ones

Seems optimistic to think that a first generation electric plane will avoid that challenge: in theory if you're only operating on electricity the kinetic efficiency doesn't matter quite so much, but 125 miles range on electric power is really quite limiting and crucially newer generation electric aircraft would be expected to offer more electric range. I guess a lot might depend on how easily it is to legally retrofit better batteries to older gen aircraft.

They'll want to sell for more than the market value of an old Saab 340, that's for sure...