First Delta Formation -- For the ***** history, delta winged aircraft fly in formation - led by the mighty Avro Vulcan bomber - for the SBAC air show opening Farnborough to-morrow (Tuesday). Bottom right and top right are 707 As developed to test the new delta plan form in high speed flight. Top centre flies the 707B, first of the delta w1nged planes used to investigate low speed flying characteristics. Lower center is the two seat dual control 707C, designed to help pilots become familiar with