Saw a blue small round object near a larger white round object on RT. 2 going west in the sky in Leominster MA. At ABOUT 2030 HRS. The small blue object seemed to be following the white one. At an instance, the white one appeared to increase in brightness and started flashing on and off fast. Then the blue object followed the white one and turned a bright white as well while flashing. They then both flew across Rt. 2 from a southerly direction to the north coming very close to each other. They headed side by side going in a northwestern direction. One object gained speed and flew in front of the other and the other gave chase. As I was driving my car at about 58 miles per hour the trees on the side of the highway obstructed my view and I lost sight of them.