Warrior of Scorpio — Alan Burt Akers

The third book of the Dray Prescot series.

Once again in the grip of the Star Lords of the Constellation Scorpio, Dray Prescot finds himself torn from the battles of the Inner Sea for a mission in the air. For it was now his mission to carry his beloved Delia by airboat to that far kingdom, Vallia, from whence she had come. But the route lay across the gaunt mountains and the shadowy jungles of the Hostile Territories -- and there Dray was to be plunged among stranger peoples and more fantastic challenges than even his Kregen princess had known...