Optimal transient energy growths supported by the plane Bickley jet are computed for a set of spanwise wavenumbers and Reynolds numbers. It is shown that the maximum energy amplification is proportional to the square of the Reynolds number. The computed optimal streamwise vortices are then used to efficiently force finite amplitude streaks that are shown to stabilize the jet's powerful inflectional instability, which is clearly relevant for a number of applications in the control of free shear flows.