For high speed aircraft formation switching systems, this paper proposes a performance function-based finite-time control method to achieve rapid and stable formation switching in dynamic mission scenarios. First, a formation dynamics model comprising a leader and followers is established, and a novel finite-time cooperative controller is designed to ensure rapid convergence to the desired formation in each mode. Second, to address formation switching triggered by mission changes, a joint decision mechanism integrating performance functions and dwell-time constraints is introduced. This mechanism evaluates the system state in real-time and incorporates dwell-time constraints, ensuring switching is triggered only when both performance requirements are satisfied and dwell-time conditions are met. This design effectively guarantees smooth transitions and global stability during the switching process. Finally, simulation results validate the effectiveness and reliability of the proposed formation switching method.