Pax failure

Hi, since the last update I have a problem with pax not turning up at the airport.
I first started to notice when I realized that I was losing money. Pax still arrive in the planes but don’t turn up for departure, it doesn’t happen all at once its a gradual thing, that’s why you don’t realize what’s happening at first but it always ends with none at all arriving. The public transport system still runs as it should as if bringing pax to airport. This is the the forth airport I have had ruined in this way, meaning I have to abandon before I can open up the other half of the airport. The problem always seems to start when I get to about a dozen stands (medium). There seems to be nothing in F10 that can help me and I am wondering if any one else out there has had similar problems and if so what was you able to do about it. I don’t think my computer is underperforming as I am quad core 3.50 ghz, 16 gb ram, 64 bit. In any case I was quite able to build full size airports with no problems before the bigbird update. Hope someone can help and thanks. Mogso.