The majority aren’t staying grounded because of fears about contracting the virus they’re staying grounded because of ridiculous quarantine rules introduced by various governments that make travel utterly pointless in their current form. Take Jersey for example - already testing on arrival - since the States recently decided to introduce the colour banding system for U.K. regions this makes the vast majority of areas Amber at the very least. This means five days isolation until your second test result. Since this policy has been introduced the passenger loads on LHR-JER have gone from very respectable to utterly dire. This has nothing to do with fears of travelling and everything to do with practicalities.