This is a beautiful sheet of 4 stamps, issued by Guinea-Bissau in 2011, commemorating the 100th anniversary of the first airmail flight by featuring aircrafts. Also honored on the sheet are ballooning pioneer John Wise, airplane inventors Orville & Wilbur Wright, and the first official airmail flight pilot Henri Pequet. The sheet is Post Office fresh, mint never hinged, and F/VF.