How do flying fishes use their pelvic fins during flight?

In species of flying fish that possess four-winged anatomy, such as the California flying fish, the pelvic fins play a functional role during their aerial glides.1

While the fish is submerged and preparing for takeoff, its fins are held tightly against its body. Once the fish breaks the surface and becomes airborne, these enlarged, winglike pelvic fins are extended to assist in gliding. Along with the pectoral fins, the pelvic fins help the fish maintain its position in the air until its forward velocity is eventually lost.12