I went outside to check the temp and heard a jet (a private jet) overhead. we are under the landing approach to ft myers international airport. planes are around 4,000 feet over our house. i just happened to glance up as i heard it directly overhead and then saw a small white object which i would guess the size of a beachball or basketball. it approached at about a 45 degree angle from the planes right rear at a speed faster than the plane and then took up a position in an area that would be considered a blind spot in a car. it maintained this position for about a mile and then fell back and passed behind the plane from right to left. i watched it for another 10 seconds and then it either winked out or flew beyond visible range. its movements were very precise with instant directional changes.