Costa Rica, Airmail Semi-Official, 1921, 1c First Airmail Semi-Official. Natural straight edge at right, light purple town cancel, F.-V.F., very rare, this was issued for use on experimental flight from San José to Managua on April 15, 1921, the plane crashed and mail was forwarded by land. Sanabria No. S1. Scott No. unlisted  Estimate $150 - 200. $0 (Image)