Any effective measure is going to consist of a combination of methods.
I don't think beefed up hangars can be the answer although any improvement will slow them down and increase the window for catching them.
Remote cameras can be defeated by jammers but airfields are big places and if well-positioned may be effective, it just needs to work once to give us a chance.
Confronting them probably isn't the best idea but getting there in time to see the vehicle and identify it may be enough to put the police on their trail (perhaps). Tagged engines would help nail them and should be the minimum action taken.
Covert wildlife cameras won't be prone to jamming and even if only any use after a break in would give us more to go on than we appear to have at the moment (we won't be made aware of any police action so shouldn't assume nothing is being done).
The CAA and plane finder etc should stop advertising the location of peoples' valuable personal property.