Systems and methods for countering an unmanned air vehicle are disclosed. Representative methods include directing an interceptor UAV toward a target UAV, and directing the interceptor UAV back to ground along a controlled flight path, for example, in response to an instruction not to engage with the target UAV, and/or in response to an unsuccessful engagement. Another representative method includes disabling the target UAV by deploying a disabling element (e.g., a net) from the interceptor UAV to contact the target UAV. Representative systems include a target acquisition system, a launch control system, and an engagement system carried by the interceptor UAV. In particular embodiments, the interceptor UAV can have a generally cylindrical fuselage, one or more fins carried by the fuselage, counter-rotating propellers carried by the fuselage, and a disabling system that is configured to disable the target UAV.