Create new recency item in employee recency management software with expiry on relevant deadline.
Send email to all staff telling them to get vaccinated and send in certificate.
As staff send in certificates, upload them to recency management software.
After deadline send list of unvaccinated staff to HR for termination.
EndEx.
Everyone else look on in glee as selfish anti-vaxxers (who also often were the ones pushing cuckoo conspiracy theories in the flight deck) disappear off the seniority list and that path to command becomes clearer.