Heading home on I-77 north at approximately 6:20 pm 11/03/2014, had just topped Flat Top Mountain. Extremely clear night, I observed 2 planes flying due east. As I was watching the planes, at a much lower altitude a light appeared and grew brighter and once it got to it's brightest, it sped east with no sound or trail behind it. This all happened in a span of 7 to 10 seconds. After it was gone the planes were still moving east also. Not sure what it was I saw, but as soon as I walked in the house I asked my family if they heard a sonic boom or anything loud, they said they heard nothing nor saw anything from home.