Recently,　unmanned　aerial　vehicle　(UAV)　cooperation　networks　have　attached　much　attention　due　to　their　successful　applications　in　complex　military　and　civilian　missions.　In　this　paper,　we　propose　a　navigation　data-assisted　optimal　opportunistic　spectrum　access　scheme　for　wireless　communications　in　heterogeneous　UAV　networks,　to　achieve　maximized　data　rate　by　flexibly　scheduling　the　spectrum　subbands.　The　system　architecture　is　introduced,　and　thanks　to　the　navigation　data　that　is　always　available　locally　at　the　entities　in　the　network,　prediction　of　wireless　link　quality　and　routing　information　can　be　obtained　to　assist　subband　allocations.　Furthermore,　the　spectrum　allocation　process　is　formulated　as　an　optimization　problem.　Simulation　results　are　also　presented　to　demonstrate　the　significant　performance　improvement　of　the　proposed　scheme　compared　to　the　existing　one.　©　2015　IEEE.