strange perfect straight lights that kept formation .

walking the dog at around 5:15 , clear sky just as i looked up there was a perfect straight line of lights that kept its formation as it took off across the sky and disappeared over the sky .it travelled fast but not at a super pace it took about 30 seconds to vanish. not one light was out of shape a plane was flashing some distance away with a tail behind it but that was flashing as it came the other way the lights was different no flashing warning light at the front , it was not a plain trail left in the sky as i could make out its formation as i went off with trail behind it.
there was 20 ish lights i have some footage in a phone video but it was taken at night but can make out the anomaly .