On July 30th 2020, SOU airport owners (Ferrovial) - which own AGS (Aberdeen Glasgow and Southampton Airports), issued their First Half results for 2020:
https://static.ferrovial.com/wp-cont...entation-1.pdf
AGS is on page 11. You can see what they say about money. Assuming planning approval for the SOU runway extension is granted - it should be - that does not mean that the airport owners (who also own a large share of Heathrow - pages 9&10), will be willing to pay for it.
On the basis of current indications, it is not unlikely that all AGS airports could be sold to raise cash needed by Ferrovial elsewhere - (eg. LHR).
In the meantime, SOU will do just fine backfilling the Flybe routes, but in common with other airports in Europe, recovery to even 2019 levels will take years, extension or not.
https://www.iata.org/en/iata-reposit...ravel-outlook/
FF