Small and extremely bright intermitten white light. High altitude on clear and sunny Labor Day. Did not move for at least 40 minutes.On Sunday, September 6th from 12:50pm to approximately 1:30pm in Bayville, NY. The sky was clear blue and no clouds. my girlfriend and i observed a small but incredible bright flashing object. The best description would be akin to seeing a very bright planet shining in a clear night sky but this was occurring during the early afternoon. The sun was very high in the sky at this time. The object was to the North at about the 11'oclock position. The object never moved. It was stationary. The flashes would flash very bright for approx 3 seconds and then lessen to planetary brightness for approximately 3 seconds. This would repeat and there would be a similar period of intermittent brightness. This was a recurrent cycle that did not deviate. The intensity of the flashes were reminiscent of a mirror reflecting pure sunlight. It was such a fine point of bright light that the passenger jets in the area completely dwarfed it. I thought maybe it was a mylar balloon, satellite or an actual planet but it did not move or decrease in intensity for the 35-40 minutes i observed it. I did not watch it go away because I was watching for a long time and my girlfriend wanted us to enjoy our kayaking together.Note: Polarized sunglasses helped see object better.