This lecture is being given primarily because of the growing tide of concern felt by persons engaged in the class of flying described in the title at what seems to them to be the growing number of prosecutions each year under the Civil Aviation Act 1949 and delegated legislation made under it. During 1966-1967 and 1968 a few low flying cases achieved prominence because the charges were dismissed upon the basis that the prosecution's evidence was inadequate to discharge the burden of proof of low flying. These low flying cases angered not only those directly involved in them but also many persons in the general aviation movement, because it seemed to them unfair that prosecutions should be begun on poor evidence, that large sums of money and a great deal of time and trouble should have to be spent on the defences of them, and that inadequate costs should be recovered from local funds to compensate successful defendants for the costs incurred in their own defences. However, I have chosen to interpret the title as including reference to certain other legal topics outside the criminal.