A steering aid system for altitude and horizontal speed of an aircraft (4) includes: a measuring device (22) for delivering a measured signal based on the aircraft altitude and horizontal speed, a common predetermined reference value (26) for the aircraft altitude and horizontal speed, and elements (20) for slaving the signal to the reference value by pitch loop, the elements being adapted to vary automatically the pitch and/or propulsive performance of the lifting members to lock the measured signal to the reference value.