China plans to achieve airline-flight-mode space transportation between ground and orbit， as well as between orbit and orbit by 2045. Cross domain vehicles， due to their ability to cross speed， airspace， and media domains， can achieve flight-based back-and-forth transportation between space and earth. Their special strategic value have been highly valued by countries around the world. The flight process of cross domain vehicles requires multiple high-speed and complex flight stages， which puts higher requirements on the reliability and safety of navigation systems. Therefore， there is an urgent need to develop autonomous navigation methods for cross domain vehicles for airline-flight-mode space transportation. To address this issue， this paper proposes a heterogeneous multi-source integrated navigation method for cross domain vehicles based on inertial/celestial deep fusion to solve the autonomous navigation problem of cross domain vehicles in achieving flight oriented space transportation. The results show that the method proposed can fully utilize the complementary advantages of inertial navigation and celestial navigation， correct navigation errors， effectively improve the output accuracy and reliability of cross domain vehicles navigation systems in complex flight environments， ensure the safe and reliable operation of navigation systems of cross domain vehicles， and enhance their seamless information fusion ability in the entire flight stage， accumulating technologies for realizing the concept of airline-flight-mode space transportation.