To solve the problem of UAV formation control,an aircraft formation control algorithm based on the combination of virtual lead aircraft and nonlinear sight guidance law is designed.The formation flying process is divided into two phases,that is,route flight and route switching.In the phase of route flight,based on the virtual lead aircraft,the reference points are generated by using the nonlinear sight guidance law,the desired reference points for the formation aircraft are generated based on the geometric position of the formation,and the roll angle command needed for each aircraft to maintain the formation is obtained.In the phase of route switching,the virtual lead aircraft adopts circular arc flight,and the formation aircraft takes the virtual lead aircraft as the desired reference points to generate the roll angle command needed for formation keeping.The velocity command is obtained from the distance error between the virtual aircraft and the formation aircraft.Based on the nonlinear simulation model of a fixed-wing aircraft,a typical “V” formation is designed.The reliability and control accuracy of the multi-aircraft formation control algorithm in the phases of route flight and route switching are verified by numerical simulations.