Any person subject to this Act, being the pilot of an aircraft belonging to or in the service of the Coast Guard, who--
         (a) flies it at a height lower than the minimum height authorised by his Commanding Officer except while taking off or landing; or
         (b) flies it so as to cause or likely to cause unnecessary annoyance to any person,
shall, on conviction by a Coast Guard Court, be liable to suffer imprisonment for a term which may extend to two years or such less punishment as is in this Act mentioned.