Horizontal moving object with bright red and green lights.

I saw this object outside my 2nd floor bedroom window.  It was very bright with green and red lights (not blinking), spherical shaped that went horizontal past the window about 150 feet away.  I thought it was a drone but drones don't move horizontal without tilting.  This is a very rural area and not much in the area.  There is a private airport about 1 mile away, but this also did not move like an airplane or helicopter.  Also, aircraft would not fly that low to the ground.  I estimate about 3-4 feet in diameter.