I went on Sunday and got in with little or no trouble. 10 or 15 mins of very slow moving traffic when in sight of the airfield was all I experienced. The traffic was directed along past the airfield and the people with passes filtered out as we went along. I and the other casual visitors were directed into a large field to park our cars in across the road behind the land war museum. From here I walked back to the road crossed to the entry gate and paid for a ticket to get in. Slightly more hassle than when I last visited but not a major problem. Generally it appeared very well organized with a lot of people out for the day with their families having fun.
I have put few photos on Facebook: Duxford 5 Sept 2010 | Facebook