It reminded me of an F-111 doing a dump and burn.
In September or October 1991 I was outside Wagga Wagga and saw what I first thought were three RAAF aircraft doing a dump & burn, but then noticed a number of smaller burning objects on parallel courses. I watched these as they passed north-south, for between 30 & 60 seconds, by my estimation. They were reported over a wide area.
It was very quiet, no traffic noise, and it seemed to me that I could hear the sound from these, like a high-flying jet aircraft. Would one of our astronomically knowledgeable members be able to comment if this was feasible, or a figment of my imagination.