Niknak,
I agree with your comments but can't see why this would be a problem for Ryanair since they shun airports like Schiphol. If another loco..Easyjet/BMIbaby etc came to HUY they might deem the demand for a service to Amsterdam is not sufficient. I suspect that @80% of KLM passengers connect at Schiphol onto other flights. Looking at other UK airports; surely if Teeside, Exeter, Bournemouth etc can support loco services then why not Humberside?
Matt