Bidspirit auction | Worldwide Air Post Stamps and

Worldwide Air Post Stamps and Postal History - Austria - Pioneer Flights - 1918, two covers on line Vienna - Lemberg (now L'viv), both franked by four values, including complete air post set on gray paper, stamp of 2.50k/3k with perforation 12½ x11½ (dated May 7) and on white paper (dated July 7), all appropriate markings and arrival date stamps on reverse, mostly VF, Est. $300 -$400, Scott #C1-3, C1a‑3a