I haven't seen flashes per say but I have seen what look like ur average star blinking in a rhythmic fashion stationary in the sky as well as ones that suddenly 'turn off'. I've seen a few times same 'star' looking things move on a parabolic trajectory before disappearing. I'm a licensed aircraft mechanic so I know airplanes very well & can say with confidence that these are no aircraft. & I have my whole life had a fascination with flight & space & have seen my fair share of satellites planets etc. & these are definitely not these as well. No idea what they are, they aren't any type of conventional acft/space craft though that's for sure. My money would be on black budget military acft/space craft or there alien. There's just no way currently to make that determination conclusively.