Of course, the fuddy duddy magistrates (with whom common sense is a rare trait indeed and legal training even rarer) were probably awed by having such a magnificent case in front of them and quickly dispatched it up the ladder with shaking hands.
I know a bit about this as I work in a court that serves a large airport and I have seen similar cases. The case was sent to the Crown Court because the usual starting point is about 12 months custody, which is beyond JPs' powers. The pilot concerned got off towards the lighter end of the scale for reasons that I can't comment on, but I must confess to surprise at the name of the judge concerned as he is known for dishing out stiff sentences. I have seen him give someone nine years for a failed handbag snatch.
Just to clarify something, the breath testing machines in police stations are not legally calibrated for the very low aviation limit, so suspects are always given a blood test and bailed to return later when the results have come back.