Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems. To do that, we review the literature, present and adopt a criterion to determine the coefficients of a control system which should optimize the trajectory of the control signal during the switching between two modes. The chosen criteria are the classical integral of the time times the square of the error (ITSE), and the integral of the time times the module of the error (ITME). Effectively, each transition will be done by a subsystem specific for it, according to the selected criterion. The system will be chosen from relevant cases of the literature. The simulations will be made in MATRIXx@ or MATLAB@. The results obtained so far suggest that the proposed strategy effectively reduces the steps or overshootings in the transients between those switching modes and can contribute for the reliability and mantainability of aerospace and automotive systems.