Despite their differences, certain parts of Friedrich Nietzsche's Beyond Good and Evil and A.J. Ayer's Language, Truth and Logic have striking similarities. The most important of these is that both reject the existence of objective ethical values.
In ethics, Nietzsche's and Ayer's positions are basically the same - they see morality as descriptive of moral sentiments. Thus, no "true ethical system" can exist. It also follows that one cannot be correct or incorrect in matters of ethics, and both Nietzsche and Ayer agree on this. Thus, both reject absolute values. However, they accept morality as a genuine sphere of human life - neither is a nihilist, although Nietzsche is often labelled as one.
They both believe that the morals of a particular person or the ethical system of a moral philosopher reflect the personality of the thinker. The clearest example of this is the case of Immanuel Kant, which both thinkers discuss in their works. More generally, they believe that the prevailing moral sentiments reflect the character of an age.
Both see morality as a necessarily social phenomenon, and as a utilization of power. Both can be seen to suggest that there is much cruelty and incitement of fear in the history of morality. Furthermore, Ayer and Nietzsche reject the idea that that which is commonly held to be good is good.
A common characteristic is pragmatism - Ayer does not put forth a pragmatic theory in Language, Truth and Logic, but the logical conclusion of his ethical thought is pragmatism. He is not a moral nihilist, and rejects absolute ethical values, so it follows that a viable conclusion is to adopt a principle and judge actions pragmatically, ie by how well they help in achieving that principle. Now, this is just what Nietzsche has done. Having accepted the furtherance of life as his principle, he judges everything by how well they comply with this.
I think that the similarities of their conclusions, despite extreme differences in style, suggest the validity and strenght thereof. The similarities of their thought, arising from different philosophical traditions, might also suggest the possibility of a reconciliation of Continental and Anglo-American philosophy. Perhaps this might pave the way for a "philosophy of the future", which is a prevalent theme in Nietzsche's work.