New Luxury Service To U.S.: Pan American World Airways "Strato" Clipper, called the world's "fastest and most luxurious" commercial passenger plane. These giant airliners will be used on Pan American's new luxury air service to the United States. The doubledecked "Strato" Clippers carry 56 passengers with individual Sleeperette seats or single-occupancy berths for each. A club lounge on the lower deck, reached by a spiral staircase within the plane, offers complete bar service. The huge Clippers