If she has got better so quickly it probably wasnt anything serious, but go to the vet if something similar happens again. my elderly budgie sometime has funny turns like that, but just because of his age (he is 12, and had a very traumatic life before we got him bieng subjected to having coffee poured over him, his tiny cage bieng knocked off its stand, 24 hr light and bieng fed biscuits. A nursing home full of demented patients and cigarette smoke is no place for a pet bird. He is now in an indoor avairy, but is still scared to go outside and will not eat anything but millet and spinach, so I think he has done pretty well to get to this age). Was it a very hot day? some birds dont cope well in heat, and panting with wings spread helps them to keep cool.
It probably wasn't her wings, but maybe she flew into the bars of her cage and is a little concussed.