Koi
I didn't suggest letting him continue flying. There are many cases where drivers have been advised not to contuinue driving...and thats the end of it, unless they fail to take theat advice. The Aviation and railways safety act power of arrest (which has nothing to do with the ANO) That power, along with every other power to arrest says May not Must.
Thats not the issue however, which is that the discrestion exists alowing a Constable not to take action if he so deicides. How many people for instance are given a warning for going through a red light. The seriousness of the offences may be differant, however the principle is the same. Having said that you are right, it would be highly unlightly that a constable would not proccede by means of arrest, if they pilot failed a screening breath test. (or caused the officer to suspect an offence of being unfit through drink or drugs)
The criminal act you mention from the ANO was vauge to say the least unless Drunk on an aircraft could be proven. The offence would now be under this new act. As to your comments about suspicion or a report is all thats required, either you have the new legislation wrong or I have misunderstood what you have said???!!!!
One final thing the only 'Airport' Police officers I can think of are in the Isle of man and Belfast. I think you mean Police Officer.