I was house sitting for my parents and it was aprox 3:am. I was alone and I was awoken by bright lights in my curtained windows with light reflections on the walls. I got up to look outside to investigate the light source(they have 3 petrolium refineries near their house). I opened the curtains and observed 3 slightly illuminated disks with porteholes on the outside in a band circumnavigating the saucers. All at once the 3 saucers rolled end over end away from the house and took off one by one with about 1 second spacings. A propane blue burst emited from the underside of each craft as they took off each going seperate ways. I heard noises comparible to a jet taking off for a split second after each one took off. Also as each saucer prepaired to take off the light/flame grew brighter and a short blue flame appeared from the bottom of the craft.