For a linearized fourth-order model describing the lateral motion of an aircraft with two controls, the stabilizing control laws analytical expressions are obtained at the lack of measurements of slip and roll angles. Analytical synthesis is based on a new approach of solving the problem of control by output. In contrast to the traditional Van der Woude approach using multilevel decomposition, the proposed approach is applicable to a wide class of systems with total dimension of control and observation vectors not exceeding the dimension of state vector. A compact formula is presented that determines the matrix of controller by output for a fourth-order dynamic system with two inputs and two outputs, provided that the indices of controllability and observability are not equal to each other. The results of simulation of control processes are given on the example of stabilization of the lateral motion of a hypothetical aircraft.