I was smoking outside when i saw, what i first thought was a flock birds flying in a "v" formation from the east. i noticed once it was overhead that there was no noise, and it instead looked like a translucent triangle or boomerang shape gliding across the sky. it moved fast; faster than commercial jets we see near mdw airport. the front end to left a wake or trail that evaporated quickly. the whole incident last about 5 seconds. from.First discovery until it was lost in the westwrn horizon.