Richard P Synergy flew a kite to an altitude of approximately 4,422 m (14,509 ft) above the point of take-off on 12 August 2000 near Kincardine, Ontario, Canada. The massive kite, with an area of 25 m² (270 ft²), was designed and built by Synergy himself.
At its maximum altitude the kite had 7.31 km (4.5 miles) of woven kevlar line connecting it to a winch on the ground. The record-breaking flight lasted 8 hr 35 min.
The kite was a high tech delta, having 270 square feet of nylon kite skin, measuring 30 feet from wing tip to wing tip, and 18 feet tall, sporting hollow fiberglass spars 1.5 inches in diameter, flying on 270 pound woven Kvlar line 3/32 inch in diameter.
Good write up on http://www.kwarc.org/bulletin/2000-10/kite.htm
Comments below may relate to previous holders of this record.