A lot of doom around this morning. Yes, I think we will shortly see the end of Flybe as we know it, but the airport will continue - don't forget there was no such thing as Flybe when the present terminal opened in 1995! There will of course be a dramatic reduction in flights, but most of the key routes will continue in one form or another. For example KLM City Hopper would probably add an addition daily flight weekdays, Aurigny and Aer Lingus Regional will continue. Blue Islands and Eastern would probably be 'up and running' after a couple of days too. The Manchester, Edinburgh and Glasgow routes would very likely be taken over by other operators reasonably quickly, as soon as resources are available, either BMI/Loganair operating high frequency with small aircraft as now, or by another operator (such as easy, using larger equipment but at a reduced frequency). Dublin and Belfast would also probably resume, most likely with Aer Lingus Regional/Stobart. The future of the 'sun routes' with Flybe has been uncertain for some time now, but I wouldn't be surprised to see BA City Flyer having a go at a few of these - perhaps Malaga/Alicante/Palma.
So, yes a short-term serious shock for SOU, but a gradual rebuild to a very sustainable 1M - 1.5M passengers over the next couple of years.