On A More Serious Note....

.... It is quite likely that there will be a volcanic eruption somewhere on Earth that disrupts air travel for months and months, in the medium term. The kind of eruptions that occur once a century or so haven't occurred in the aviation age yet but it is inevitable that one will happen at some point and it will probably occur in this century.

There are upsides to volcanic eruptions, but the economic devastation and food shortages that result are something that we have to plan for.

If a Super Volcano erupts then it is unlikely civilisation will survive in any recognisable form bit they only happen once every few hundred thousand years.