W.T. Tutte showed that if G is an arc transitive connected cubic graph then the automorphism group of G is in fact regular on s-arcs for some s ≤ 5. We analyze these arc transitive cubic graphs using the unifying concepts of the infinite cubic tree, ᴦ3 and coverings. We are able to answer a large number of questions, open and otherwise. As an example, suppose G is a 4-arc transitive cubic graph and the automorphism group of G contains a 1-regular subgroup, then G is a covering of Heawood's graph.
