In this paper, a new guidance strategy is proposed for achieving precise control of time-varying velocity aircraft with impact time and angle constraints. Traditional guidance laws assume a constant velocity of the aircraft, but the velocity varies with time in practical scenarios, which affects the guidance accuracy under impact time and angle constraints. To overcome these difficulties, a guidance strategy consisting of trajectory generation and trajectory tracking is proposed. Firstly, the reference trajectory is constructed based on the Bezier spiral, which naturally satisfies the impact angle constraint. Then, the control problem of the impact time is transformed into an adjustment problem of the trajectory length. The expression of Bezier spiral that is only related to the curvature is derived, and a new lemma describing the relationship between trajectory length and curvature is found. Furthermore, the differential flatness property of the control system is explored to design a trajectory tracking method for Bezier spiral trajectory, which applies feedback linearization of the system through higher-order information. Finally, Numerical simulations confirm the superiority of the proposed method and validate the analytic findings.