Small sphere flew in curved pattern under small plane...accelerated until it faded out.

At approximately 10:05pm I was looking at constellations through my binoculars and directly west I spotted a small plane heading east...upon viewing the plane I noticed a small white light come from the NW and it swooped under the small plane and proceeded to accelerate faster in a southernly direction.  It made a curved pattern while coming from the NW heading South SE...I lost sight of it as it faded out. Night was clear no clouds.  This is my 3rd report over the last 15 years of unknown anomalous objects flying in the sky near my home.  We live close to an Will Rogers airport, this had to have been picked up on radar.