On December 12, 2006, at 1430 Pacific standard time, an Extra Flugzeugbau GMBH EA 300/L, N91BH, veered off the runway during takeoff from runway 9R at Boulder City Municipal Airport, Boulder City, Nevada. The airplane was owned by a private company and was being operated by the Aerobatic Experience under the provisions of 14 CFR Part 91. The commercial pilot, who held an airline transport pilot certificate in multi-engine airplanes and a commercial certificate for single-engine airplanes, sustained minor injuries, and the commercial certificated passenger was not injured. The airplane sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan was filed. The local formation flight was originating at the time of the accident. The pilot reported in a written statement that the purpose of the flight was a two-airplane formation flight, of which the accident airplane was in the number two position. The pilot was acting as pilot-in-command (PIC) of the flight and seated in the rear seat, and the passenger was performing the takeoff. As the tail rose during the takeoff roll, the airplane began to swerve across the runway. The right wing came up slightly and then the airplane veered to the right and departed the runway surface. Due to the soft terrain at the runway edge, the airplane would not accelerate. The PIC noted a large drainage ditch and decided that aborting the takeoff would not be possible with the obstruction. The airplane flew over the ditch and then touched down with the right main gear on the far side of the ditch. The airplane then cartwheeled and came to rest upright with the left wing separated at its mid-section and the right wing angled upward. The passenger stated that he had purchased the aircraft flight from Aerobatic Experience with the intent of obtaining formation instruction. During the flight, both the passenger and PIC were on the controls. The airplane accelerated and the PIC told the passenger that they had a left crosswind, so they applied crosswind correction. The right wing rose and the passenger said he eased control application of the left crosswind correction. As he eased off of the correction, the airplane canted to the right. At 50-60 knots, the airplane departed the runway surface to the right and just prior to impacting a ditch, became airborne. Following the ditch, the right aileron spade impacted a fence post and the airplane cartwheeled. The Federal Aviation Administration accident coordinator responded from the Las Vegas Flight Standards District Office. A flight control continuity check was performed and movement was obtained to the rudder, elevators, and right aileron. The left aileron had separated from the left wing. Examination of the braking system showed normal operation. No mechanical malfunctions were noted.