Time: Approx: 9:00 p.m.
My family and I live in Waynesboro, PA (in south central PA a few miles from the MD border and near Raven Rock military installation) and we saw something very similar to what you described. On Saturday evening May 7, 2011 around 9:00 p.m. We saw three (3) bright orange lights, soundless and moving slowly from northeast to southwest.
The lights continued on a straight trajectory and then slowly turned due east. As they turned the lights vanished. All three objects followed the same flight path, the first one was alone, but the other two came in succession about 10 minutes after we spotted the initial light.
The 2nd and third light were visible at the same time and appeared to be about 20-30 seconds behind each other. As they turned both vanished. There was no erratic behavior or acceleration anomalies. It was just odd and no one has a clue what they were. I suggested that they may be twilight hang gliders or small, single engine airplanes, we have no clue.