At approx 19:30 I saw three aircraft flight over my house in Simpsonville SC. They were rather low in altitude and traveling at a heading of approx 28deg. It was dark and I couldn't make out a profile. There were NO standard aviation lighting. I could see clearly that each craft had two flames coming from what appeared as the engine nozzles. Again they were flying at a low altitude BUT there was NO noise whatsoever coming from them. The three were flying in single file with about a 4-5 sec interval. I don't have pics but I was able to get my wife to the door to witness the third one flying over.