This is an opinion from a friend of mine who's now doing his PhD in Optical Physics. He wasn't considering between an MSci in Physics or MEng in Aeronautical Engineering specifically as your are, but he went for the MSci in Physics over other subjects because he said it was the degree which would give him the most opportunities after graduating. And by the third year when he knew what area of work he wanted to pursue, he tailored his module options accordingly.
Another mate of mine did an MMath in Pure & Applied Mathematics. His opinion was pretty much the same. When he looked for a PhD, he could have done Electrical, Mechanical, Aeronautical or Materials Engineering, or something completely different like financial mathematics or economics.
I did my MEng in Electronic Engineering, and whilst my post-grad options were not too limited, I had far fewer options than the two mates mentioned above.
Obviously it's your call, but if it was me, I'd go with the MSci in Physics. Shop around the different Uni's that offer MSci degrees in Physics and look at their module options. Look at the research groups within the department as that will give you an insight where the academics interests lie. You may find some will offer aerospace/aeronautical modules as options. My mate did his at Imperial College.