tringular shaped object hovering while making a droning type noise. disappeared very quickly.

triangle shaped object was hovering directly above us.eggshell to grayish in color.it wasnt smooth on the bottom as we could see what i recall as being seams in its structure similiar to a aircraft. it made a electrical type of droning noise.we looked away from it very briefly at which time i remember that the dronong sound stopped.when we looked back where the object had been we saw that it was gone.we attempted to relocate it with negative results.i remember it as being a clear summer day and that our vision was not impaired by low cloud coverage.