The only plus I can see is that if you leave your car at the airport for a week or some other long term parking situation, you don't come back to a dead battery.
Assuming you aren't parked underground. Many airport parking lots are multi-tiered parking garages for density. Sure, you can park on the roof, but maybe rooftop becomes the more 'coveted' spot if this did take off.
Over the past twelve months our Leaf has sat for weeks at a time without being driven. It has never failed to “start”. When it sits at the airport, it sits in the charger spot with all the other EVS.
Many large airports and certainly the majority of airports in large metropolitan areas have underground or covered parking.
Most still have the large extended parking lots that are a bit further away. Those are always large outdoor lots, even at a place like SFO. These are more geared towards the longer term parking scenario the parent post referred to.
Normal EVs can sit for a week and not have a dead battery. There is some value to having that trickle charge but not a ton. IIRC there was a solar powered Prius where the panel powered a cabin fan and that kinda makes sense.
You'd have to remember to park on the roof!
Airports have 24/7 service to jump start your car etc.