This paper addresses the problem of trajectory planning and tracking control of groups of unmanned vehicles. The trajectory planner is aimed at satisfying the dynamic equations and constraints. The planner builds on two features of the group: (1) state equations for each member are differentially flat, and (2) inequality constraints have special structures due to proximity constraints between members. Under these assumptions, formations are made so that the dynamic equations and constraints are satisfied. Illustrative simulations of groups of unmanned ground vehicles in formations are presented. The results are also implemented on a laboratory facility with three unmanned ground vehicles.