Book cover, front and back.
Front featuring a tall, athletic young man approaching a Stearman duster aircraft, to which a surfboard has been lashed on the lower-wing base and flat against the fuselage. The young man is dressed in long surfer trunks, T-shirt, and rubber go-aheads. A pilot's crash helmet dangles by its chin strap from one hand. (See first photo attachment of crude sketch.)
Back of cover is sugar-cane field by a coco-palm-lined beach, tall cane in foreground. Emphasis on front cover is not on any beach, but on a young, athletic pilot dressed in surfer shorts, go-aheads and t-shirt who is about to board a duster to which a surfboard has been lashed. It's one scene in the novel when Tim is assigned to fly to another island to do a few days' work. He's dressed the way he usually is when he flies, and he's simply taking along his surfboard. Be sure to study the first attachment, which is my crude sketch of the front-cover concept.