bright orange lights following in formation

My son and I were sitting outside in the hot tub on Thanksgiving night (11-28-13) and around 10:20pm we noticed fairly large bright orange lights (unlike planes) traveling in single line formation from the Northeast to southwest sky. We continued to watch as they would each slowly fade away as they passed beyond us overhead. They were evenly spaced, made no sound (that we could hear), and traveled at medium speed. Neither of us had our cell phones to capture video unfortunately. We called my husband out to witness the last few. The event lasted about 5-7 minutes or so maybe. It was not a flight pattern to O'Hare, there were no planes at all in the sky, before or after the event, the entire time we were out there. It was a fairly clear night as well.