Ultimately local authority owned airports will have to be disposed of. There is no justification for council taxpayers money to be continually pumped into what will be in effect bottomless pits for the next couple of years. This will be at a time when council services v receipts will have a big hole. As high streets become devoid of retail stores and business dies as it does in a recession then there will be a lot less cash.
I would suggest total losses of Airports in 2020 probably close to £2 billion potentially higher. The issue is that no airport will be in a position to service their debt, potentially ownership may forcefully be changed as debt holders take control but what do you do in taking control of an airport when nobody is travelling.