cover Italy, 1926, Dirigible 'Norge' Trans-Polar flight cover (AAMC Z-478a), large (7x4¾") orange flight cover with printed address for the Rome-Pulham flight leg, franked with average-centered 1.25L Blue & Ultramarine (88) and with special Amundsen-Ellsworth-Nobile flight label and purple large double oval flight cachet, very fine, a scarce trans-polar dirigible flight cover (AAMC reports only 51 covers were carried on this flight segment) photo