I'm an aviation professional, flying being a small but essential part of my job. Other than that I manage people and projects, approve aircraft design work, fly aircraft, inspect aircraft, etc.
In the course of this, I probably use 90% of my aero-eng degree (Soton). But, my various pilots licenses also get used a great deal, as do various courses I've done on aircraft servicing and inspection, management, etc. It's all cumulative.
If you ONLY want to be a pilot, Aero-Eng may not be what you want to be, if you wish to be a rounded aerospace professional, I strongly recommend it.
The first half of the course is tedious consisting of much theoretical maths, aerodynamics, electromagnetic theory, materials theory, etc. I'm sorry chaps, this this stuff is essential - no fun, but essential nonetheless. Later on, it all falls into place as you start to consider more specialist subjects.
But, the 4 year MEng is only half of the 8 years minimum to become a CEng, it's one of the longest slogs of any profession. Is it worth it? That's up to the individual, but I've no regrets, I have flown, crewed, or worked on getting towards a hundred aircraft types, taken many difficult decisions, and had huge satisfaction from their results.
If you want to get onto the RAeS, by all means do so. The commitees that set the academic syllabus are too-full of professors and not full enough of working Engineers. At the moment I'm preparing a paper to them recommending changes myself (and am in the happy position of having a few worthies like Darrol Stinton and John Edgley behind me), but don't think you'll change anything in your academic career - these things take years to work their way through, sadly.
G