Yellow & blinking green; then solid green and red. Hovered; fast vertical & horizontal up and downs, turns and arches complex maneuversWhile enjoying the evening air, my girlfriend and I observed what appeared to simply be a commercial airliner making its final approach to Houston - until it stopped and hovered at an altitude of at least 1500 feet. It was mostly cloudy at the time. At first the object was a whitish-yellow light like a plane with also a blinking green light. It later changed to non-blinking green and red lights only, arranged horizontally. We were looking due west. As experienced birdwatchers, I got our binoculars for a better look. It moved more quickly, complexly and unexpectedly than any aircraft I've ever seen. It dropped and ascended vertically several times, very, very fast. It moved back and forth horizontally very fast and made several complex turning and arching maneuvers as well. My girlfriend suspected we might be seeing a "toy" remote controlled aircraft. I didn't think so. Who would be out on a cloudy night like this in the middle of the week in a residential neighborhood flying planes? It made no sound. My girlfriend has worked for a major corporation for 25 years. I'm employed in the healthcare industry.