From what I have read, it is actually a vaccine delivered by adenovirus, much more stable than mRNA. The plane thing seems pretty far fetched though.
Discussion
Then this meme and the tweet are complete bullshit as it clearly says mRNA. And inhaled vaccines have existed a long time so again, nothing to worry about.
Even if this was a thing, you could just wear an N95.
According to duck.ai, Aerosolized medicine particle size is typically 1-5 microns. N95's are supposed to be good down to 0.3 microns.
mRNA is measured in nano-scale, hance lipid NANOparticles that package them. But its not possible and almost certainly never will so still nothing to worry about
This sounds like a fucking horrible idea 
https://publications.ersnet.org/content/erjor/early/2024/12/09/2312054100758-2024