A late 1930s commercial airmail cover from W. Francisco Siebold (Servicio Para Autos), Guatemala City, Guatemala, franked with four stamps — a 10c and 15c 'Aereo Exterior' overprinted airmail pair plus 1c and 2c Quetzal definitives — tied by a violet 'Correo Internacional Guatemala' circular datestamp and bearing the bold blue diagonal 'Correo Aereo' airmail stripe, addressed to The Gibson Co., Indianapolis, USA; back bears a violet 'Servicio Interior Nocturno Guatemala' transit cancel; light age toning and minor surface wrinkling consistent with age, no tears or significant faults. Please review the scans for condition.