So... angels come across with that image because they are a spiritual messenger they carry a message from source  or that which we call God so it's a symbolic image just like demons are a symbolic image because of the christian influence which is still so prevalent today the image of an angel with wings is still something which speaks to  most of humanity and so they can show up that way but they also can and will show up in whatever other image would be best received by you here's a small side note when upper dimensional extraterrestrial life forms  appear to human kind they often come across as beings of light, and thus,  are often seen as angels many of the historical runnings which you've heard of with people and angels are actually extraterrestrial encounters 