This paper presents a new method for design of flight controllers for aircraft : feedback linearization coupled with structured singular value (mu) synthesis. Feedback linearization uses natural time-scale separation between fast and slow variables. The linear mu controller enhances robustness to parameter variations and requires no scheduling with flight condition. This methodology is applied to an angle-of-attack command system for longitudinal control of a high performance aircraft. Nonlinear simulations demonstrate that the controller satisfies handling quality requirements, provides good tracking of pilot inputs, and exhibits excellent robustness over a wide range of angles-of-attack and Mach numbers.