I can see easyJet lining up to take the best parts of the Flybe network. I'd not be surprised if easyJet opened on the larger short routes out of SOU with 319. BFS could easily be stepped up to accomdate BHD routes. BRS is a perfect alternative to CWL, I'd suggest already a large cohort of Wales/Cardiff residents go to BRS already anyway. Any viable /attractive routes would likely attract services in their own right.
The thinner niche routes like from more remote locations like EXT and NQY/ West Country would be picked up by Loganair, Stobart, Flybe, or Eastern and the government recognised where exemptions to APD should apply...
If there is demand the airlines who operate will provide jobs and sustainable services without need for public finances.
And at a time when for eg.the NHS and hospital system is under immense pressure (e.g. NI), how can the suggested £500M be even considered?