I will shortly be able to acquire a Master's degree in Aerospace Engineering. I am interested in designing aircraft as opposed to subsystems, but I am not enthusaistic about the various "system-of-systems" approach that essentially works to make new aero design codes(as opposed to new aero designs) or simply discusses(as opposed to any real technical design) potential future designs. This is the direction basic research appears to be headed. Given these circumstances, would it be wise to go beyond a Masters degree level in such a program. How useful are Ph.D.'s in Aerospace Engineering in general? Thanks.