I think that there will indeed be such startups coming up as early as next year, making use of the abundance of available aircraft and qualified personnel. But most probably not in the UK. My bet is Eastern Europe due to the lower taxes, lower labour costs, less strong competition and somewhat less uncertainty in the political and regulatory future coming with Brexit. Most probably, those will be ACMI companies providing cheap capacity to scheduled carriers in Europe and beyond. Making use of such a company during periods of high workload or while your aircraft are in maintenance is often a lot cheaper than expanding your own fleet and hiring extra personnel and it will make sense to larger airlines who won't be willing to take the risk of expansion/restoration to pre-crisis fleet sizes just yet.