The problem of tracking civil maneuvering aircrafts in the provision of air traffic control (ATC) systems by means of multiple-model (MM) estimation is considered. By constructing an appropriate set of models of maneuvers it is possible to describe how different maneuvers influence the state estimation process performed by a Kalman filter (KF) based on a nonmaneuver model of motion. This methodology leads to a diagnostic subsystem, which supports an adaptive switched MM (SMM) state estimator of a hard-decision type, based on KFs designed to fit certain parts of the object's trajectory. With an equivalent set of dynamic models an alternative soft-decision approach uses an interacting MM (IMM) filter scheme. Both the SMM and IMM filters are evaluated by simulations based on the recommendations of EUROCONTROL.