You could also email the airport to see what summer traffic they have. I had the same problem with Pula, as I was trying to get my mum and dad there for his birthday...He is from Croatia..and they came back with a list of summer ops from the UK.
Is it Split specifically you want to go too? I ask because you can fly to Dubrovnik and transfer from there...Take about 2-3 hours....Flybe have flights, although I think they may be once a week...
I do find it strange that there seems to be less flights than last year and even the Reijka flights that EZY operated last year are not happening this year. The place is certainly becoming more popular.
Thanks
2J&D