I don't think slot times have much of a meaning in the GA context. I've had slots myself - usually a ~ 10 minute delay - and it's a bit of a joke when you then spend the next 5 hours flying through airspace which is so obviously devoid of traffic at anywhere near that level.
Plus the fact that my GS is going to vary far more than the slot duration so if the slot was dictated by something a long way down the line, or even the destination, it would be meaningless.
ISTM that a lot of slots just pop out of the computer but have no connection to any real situation down the line. In N Europe, just about everything is under close radar control.
Back to the subject, airfields are desperate to make ends meet, and they will give all priority they can to any traffic that looks even remotely commercial. This isn't right but in the absence of a US-style taxpayer subsidy (or a French-style local chamber of commerce funding) this is only going to get worse.
This pressure also means that we are sure to get more idiotic managements like they have at Norwich, with loads of security staff standing around desperately trying to look important (and jacking up the landing fees), toothpaste confiscation on the way out to your spamcan, etc.
I see only one way out of this and that is a concerted effort on the planning system, to create completely new but small GA airfields. They will not have PPL training going on but will cater for everybody else.
Interestingly, the former Iron Curtain is opening up to GA, with avgas, cheap landings, and basically doing all they can to stimulate GA business at every level, from spamcans to bizjets. Clearly they are doing a taxpayer subsidy, but these people aren't stupid and they have obviously judged this is the future. Not exactly hard - one only has to look at what contribution GA is making to the US economy
