S-43 Flying BoatSikorsky S 43 Flying Boat Pan American Airlines. The last model of the Sikorsky flying boats was launched on June 1, 1935. Equipped with two 750hp engines, a top speed of 190mph, and a range of 775 miles, the S 43 reclaimed some of the commercial interest that the original S 38 had brought Sikorsky from his buyers. Filling the gap left by its predecessor, the S 43 set four payload to height records one year after its inception and reached a maximum