plawolf
Lieutenant General
So... we don't know why those buses were there?
CAC company day out/picnic?
A more serious guess would be maybe some sort of open day experience for school/university kids(maybe even a prize for doing well in exams - like the top few hundred in national science exams or something like that).
Show them around the unrestricted areas, maybe even a cheeky peek at some JF17s or J10s fresh off the assembly lines, all that sort of thing to get the kids interested in science and hopefully become China's next generation of designers and engineers. And when that happens for some of them, they will have a special place in their hearts for CAC because of this experience and be more likely to want to work for them.
BAE systems had a similar thing in the UK when I was studying my a-levels. Only they were sexist and only offered the chance to girls. One of my good friends went and saw the Typhoon manufacturing line and even had a joyride in a Tornado.
When I asked her how the day was, she said 'Meh' and didn't like it when the Tornado pilot did some 'loopy turny things'... I am as speechless now thinking back as I was then. :/