Nah.
Outside air is much thinner than we need. Using it would be VERY expensive!
I think a ‘hot box’ heating system would be the thing.
But I still can’t find info on brief high-temp effects on covid.
Though it’s known to prefer cold.
“Outside air is much thinner than we need. Using it would be VERY expensive!”
Actually, the air gets compressed by the engines, and then some of it is diverted to the air conditioning/pressurization systems (called ‘bleed air’). It is both hot and compressed...but it is air meant for combustion (and thrust), so there is a fuel consumption hit - maybe 5% of simply recirculating air (but I don’t know for sure).
It is doable...and should be considered, since airlines will soon be fighting for their survival.