Green aside, this was an interesting video explaining that for short flights electric planes are extremely lucrative https://youtu.be/aH4b3sAs-l8 [wendover]
That’s correct - one of the proposed treatments for coronavirus is synthetically generated antibodies for seriously ill patients; it won’t teach the immune system as you said but reduces viral load.
The case fatality rate of being 80 years old is 5.77%. Each year this many people age 80 die of various ailments. I don’t remember staying home for months praying this number goes down.