Contrails as a Metaphor for Covid-19

I like metaphors, using something concrete to grasp ideas. I was thinking about Covid-19 (surprisingly!) this morning, specifically the process by which the virus spreads. What gets complicated to think about is the elapse of time, particularly since I tend to resist binary choices--a person is infected or not.

So here's my metaphor:  think of an infected person as a jet plane flying in a clear sky, particularly a older one.  The plane leaves a contrail behind it, which over time loses its structure and dissolves into nothing.  The contrail represents the virus particles being

Nowfly another plane through the contrail, representing an uninfected person.  If the contrail is well structured the person is more likely to be infected than if time has passed or winds have dispersed it.