3 lights "disguised" as a plane

3 objects that I, at first, assumed was a small plane but it made no noise, sped across a clear and cold night. The 3 objects then contracted their formation until they nearly touched. They then took off, 2 along the horizon {1 north,1 south} while the 3rd{formation leader}went up.I kept them in my field of vision for 2-3 seconds until all I could do was track the leader.3-4 seconds of that and then it lost me. They were white lights that seemed to mimic airplane lights, until I noticed them. I know it sounds funny, but I believe they knew I was watching, so they abandoned their charade, in a flamboyant and blatant display of their technology. Then again, if they were so intelligent,why would they neglect the sonic aspect of their disguise? I would've stopped watching before all the good stuff happened if I'd heard anything. It was a clear and silent night.