London-New York By 'Delta' -- An artist's impression of the Avro Atlantic, the revolutionary new delta-wing airliner which promises for Britain continued technical leadership in civil aviation. It makes possible within a few years non-stop transatlantic passenger flights between London and New York in under seven hours in the westerly direction and under 5? hours eastbound. The Atlantic, powered by four turbo-jet engines is a civil version of Avro's famous bomber, the Vulcan. The new liner, 145