Monaco 371-390, C49-C50 hinged

Monaco 371-390, C49-C50, hinged, $109.80. Michel 538-559. Early & modern postal transport surcharged with new value, 1956. Carrier pigeon, Sikorsky helicopter; Old railroad engine, modern locomotive; Old monoplane, Comet airliner; Steam automobile, Sabre sport car; da Vinci's flying machine, Rocket; Post rider, motorcyclist.