What is the precise difference between VTL and non VTL flights bar the quarantine restriction on arrival?
Are VTL flights only open to residents of the countries on the approved list (or people who have only been in those countries in the last 2 weeks) - so someone could say board a VTL flight at Heathrow after having travelled say from Copenhagen or Paris or Amsterdam but not from Dublin or Stockholm or Oslo (as Ireland, Norway and Sweden aren't on the approved list).
It seems to be entirely about numbers and money - larger European nations who are likely to send more tourists to Singapore being prioritise ahead of smaller ones irrespective of caseloads?
Unless its to prevent mixing of residents of approved and non approved nations why aren't all flights from approved nations VTL?