Vertical takeoff and landing (VTOL) aircrafts are characterized by large flight envelopes and significant variations in flight operational conditions, making the analysis of flight envelopes and the design of controllers inherent challenges. This study focused on a tilt-body VTOL aircraft, analyzing its longitudinal flight envelope, namely transition corridors. It demonstrated that the tilt-body have a broad flight envelope and designed a longitudinal flight controller based on transition corridor trimming and total energy control theory. The theoretical approach was validated through simulation, achieving full-speed range level flight control and effective longitudinal flight control for the tilt-body. Simulation results show that this method can compensate for nonlinearities in the model and exhibits robustness, allowing the tilt-body aircraft to demonstrate excellent flight performance during transition flight. This research provides valuable insights and guidance for the analysis and control of a class of VTOL aircraft, particularly significant for the design of new VTOL configurations.