Uniform worn in public
I see enough airmen and squaddies around the local Sainsburys in uniform but not wearing headgear. Why should a civil airport be different? The Government isn't proud of its Armed Forces and the public are hardly aware of them. They are more likely to be shot in uniform in the sandpit(s) than when they are going about their business in UK. If they are shot at in an airport then it shows security is slack IMHO.