I doubt that he has any special knowledge that provides an edge; nobody knows what the fallout will be from all of this or when/if a vaccine will be developed.

More likely, he’s just thinking about the same facts differently than others. Buffett tends to be quite cautious with regards to potential catastrophic failures, so he’s probably more focused on all of the ways that airlines, banks, etc. might lose a ton of money rather than worrying about missing out on the recovery.