It is a popular misconception that angels and other winged humanoids have wings attacked to their shoulder blades. This is implausible because the shoulder blades are so far from the center of gravity. A creature with a human-like body and wings at the shoulder blades could only fly in an upright position like a hummingbird. That's fine for hovering around in the sky, singing hosannas and the like, but it would be a real drag in forward flight as the air resistance of an upright body moving forward is much larger than the air resistance of a prone body moving forward ("drag", get it? Air resistance is "drag". It's a pun; I wrote, "It would be a real drag" which meant "It would be a bad thing" and also meant "It would cause excessive air resistance" because of the double meaning of drag, the colloquial meaning and the techno-colloquial meaning (I just made up the word "techno-colloquial"). The other colloquial meaning of "drag", namely, being dressed in women's clothing for a man, doesn't come into the pun. I tried to think of a way to make it a three-way pun, but couldn't come up with anything).
In order for the wings to work properly in forward flight, they would have to be attached to the hips, not the shoulder blades. This would let the flyer lay out prone as he flew forward, reducing air resistance (also known as "drag") and allowing him to fly at higher speeds with less exertion. Furthermore, the hip bones are larger and stronger than the shoulder blades, providing a firmer foundation for wings that are bearing the weight of the entire body. Of course, the hips would need an additional pair of sockets and I'm not sure how that would fit in except by growing the bones out from the back to make room, which wouldn't be very esthetic.
Another disadvantage of having wings attached to the hip bone is that it looks a bit dorky in flight. It could still look good when standing on the ground because the wings could sweep up from the hips to a point above the head and then bend back down almost vertically at the joint where you break the wing to make drumettes (you know, those pieces in hot wings that look like little drumsticks. Not that I would want to make hot wings out of flying humanoids or anything, but if I did, I would use genuine Buffalo-style hot sauce and not one of the poorer imitations you get at some restaurants like Hooters). A lot of the pictures I've seen of standing angels and other standing flying humanoids could even be interpreted in this way --with the wings attached at the hip.
However, there is a middle ground (that was another pun, see if you can figure it out); the center of gravity is at the hips, but only when the arms are at the sides. I don't know if we want any humanoids flying around with their arms at their sides; it smacks of hotdogging. No, the proper position for a flying humanoid is the Superman prone flying position with the arms out front to improve streamlining and to keep you from smacking into a mountain head-first in the dark. This position moves the center of gravity forward several inches into a position just below the rib cage.
Standard-issue humanoids don't have a strong bone in that area to attach the wings to; we would have to manufacture one. I propose that the lowest rib become much more massive and curve downward to meet the hip bone which is sending a massive protrusion upward. The two bones would fuse together into a socket during fetal development, providing a stable platform for the wings. Of course, this takes up a lot of room in the torso, but that's OK, because flying humanoids don't need a large stomach and the many feet of intestines; they only drink nectar or suck blood or have some other dietary limitations that require much less digestion machinery.
This placement of the wing also allows for more agility in flight. By bringing their arms to their sides, the winged humanoids shift the center of gravity below the wings, which makes for easier, naturally-balanced landing and hovering. You might be thinking, "hah, you forgot something, Doc, you idiot. What about the opposite? When the wings were at the hips, the winged people could shift their center of gravity above the wings by moving their arms forward, allowing quicker dives, which may be important for avoiding gryphons and duck hunters". My response is, first, there is no need for name calling. Second, please refer to them as "winged humanoids" rather than "winged people" because I'm trying to keep the discussion more general. Third, I haven't eliminated the possibility of moving the center of gravity forward, I've only reduced the maximum effect. Our winged humanoids can still curl up their legs to bring the center of gravity above the wings for a dive. Granted, there would be more effect if they could curl up their legs and extend their arms, but I think the increase in flexibility of the system is a good trade-off of for the decrease in dive convenience.
Still another advantage of the middle-ground solution for wing placement (pun again) is that by moving the socket into the torso, we remove that unsightly protrusion of the back of the hip bone and thereby make it possible for flying girls to have nice tushes. This is an advantage for three reasons: first, an attractive body helps improve the self-esteem of female humanoids, second, comic-book artists don't have the headache of making sure that their winged women never show their tush, and the third reason should be obvious.