Air Arrow Shows Shape Of Planes to Come -- This air-to-air picture gives a good view of the underside of the new Avro 707A Delta high-Speed research aircraft, during one of its successful test flights. Clearly shown are the air intakes at the wing roots, a future distinguishing the plane from the earlier Avro 707B, which had a single intake behind the cockpit. Since the 707A first flew in July, it has become increasingly clear that the delta shake has come to stay, one of its main advantages bei