Sometimes you will be better off enquiring at an unfamiliar airfield first.
These byelaws are usually aimed at people who may be photographing for commercial purposes ....just think how many people have phones with built in cameras on the site , they cannot be controlled. Many airfields/airports in the UK have similar byelaws with regard photography.
Best to ask first , to be honest not many photos seem to appear from Oxford Airport with regard enthusiasts taking photos. Visited the place eons ago when it was CSE , and I had to get permission then to take photos , no fancy biz jets in those days - just spamcan's and seneca's .
