The issue, as I understand it, is all about weight. Putting two different power systems on board takes away all of the benefits of using one or the other exclusively.
At least for fixed wing aircraft, there is actually a bit of opening where hybrids could make sense: planes need big power reserves relative to their cruise power demand (or relative to moderate climb) for takeoff and landing abort capability. That extra power needs very little endurance and since electric is much heavier than fossil per Wh, but lighter per W, burning fuel for baseline demand augmented with batteries for peak can be a
meaningful optimization.
I would expect to be a scaling point past which choosing gasoline over batteries becomes more efficient. Maybe common electric flying vehicles have not reached that size point yet.
I think that it is not a size point but an endurance point. A camera drone can be useful even with just five minutes on a single battery pack (your audience might actually be grateful if those overhead takes are less endless ;)). But a big commercial liner that has to be in final approach after only five minutes in the air would be very, very pointless.