intense flashing lights, knocked off our chairs

Sitting in a lawn chair with a good friend of mine in the evening of September 1974. We were looking at the sky and winding our evening down. Without a warning, no noise, no sightings. Intensly bright flashing white lights passed over us with incredable speed. We were both knocked backwards off our lawn chairs.  Ther were 5 flashes in total but to this day I'm not to sure if it was the shock of seeing lights so amazingly bright or if it was as if we were the only things in the area that got caught up in its wake as it passed by us so fast. We did tell some friends but after the response we got we decided not to share this incident any longer with any one else.
The lights seemed to start off in the distance with only one flash. We both started to ask if the other had seen it. Before we knew it or could even finnish asking the other if he had seen it ,the light was above us and flashing with such intense brightness. To this day I am amazed at what I saw and will never forget it
Witness elects to remain totally anonymous.  PD