In this paper, a distributed robust feedback control strategy with inter-vehicle collision avoidance is proposed for formation and reconfiguration control of a team of VTOL UAVs. A potential-field approach is used to generate a desired velocity for each UAV which ensures that the team of UAVs can perform formation and reconfiguration, avoid inter-vehicle collision as well as track a specified virtual leader. Each UAV is controlled to track its desired velocity subject to dynamic constraints. The proposed feedback control is robust against error disturbances due to dynamic constraints and measurement noise. A formation flight test of three quadrotor UAVs demonstrates the effectiveness and robustness of the proposed formation control strategy.