On December 10, 1995, at 2330 central standard time, a Beech B90, N551SS, operated by Executive Aviation, Eden Prairie, Minnesota, collided with a hangar during taxi from landing at the Flying Cloud Airport, Eden Prairie, Minnesota. The airplane was substantially damaged. The airplane had been flown without the operator's authorization. The student pilot was not injured. Visual meteorological conditions prevailed and no flight plan was filed. Two witnesses who worked at the airport reported seeing the airplane airborne prior to the accident. One of these witnesses stated what first caught his attention was the airplane taxiing "very quickly." They then saw the airplane takeoff on runway 36. One of these witnesses reported the airplane circled over the airport at a low altitude, landed on runway 27, then taxied back up the parallel runway at a high speed. The airplane then departed on runway 27 and "made a left traffic pattern which was flown very abruptly with a lot of climbing and descending." The airplane then did a touch and go on runway 27, circled the traffic pattern and came back and landed on runway 27 once again. The airplane then taxied up to the northeast hangar area. The witnesses got in their vehicle and drove to the area. One witness reported seeing someone running out of the airplane into the hangar. The witnesses returned to their facility and called the Executive Aviation, the airplane operator, who stated the airplane was not scheduled to be flown. The witness stated that as they were talking on the telephone the airplane taxied out again and took off on runway 27. He stated the airplane made on full stop landing then taxied around on the taxiways avoiding Executive Aviation's jeep. The witnesses stated the airplane then taxied back to the northeast hangar area at which time they once again followed it. They stated that upon reaching the hangar area they saw a person running away. One of the witnesses chased the person "... for about one block where he stopped covered his face and bent down. I asked him to sit down, but to no vail. He then continued running north." This witness then returned to the airport. The other witness stated that after reaching the hangar area he noticed the airplane was "sitting askew in the alleyway and upon further inspection we found the right wing in contact with a hangar." An employee of Executive Aviation stated that after being called about the airplane he entered a vehicle and drove down to the runway where he saw the airplane land. He reported that he could not see the registration number so he drove to the hangar where the airplane was kept and noticed it was not there. He continued to report, "Then I'm back on the landing strip watching aircraft which is avoiding me. I drive to exec ramp and the plane taxies to hangar. I follow. I see aircraft stop and person opening door and running." The police located the suspected pilot at his residence. A jacket which belonged to the pilot was later identified as being the same jacket that the person running away from the airplane was wearing. The pilot was given an intoxilizer test which indicated a value of .06%. The pilot was sent a NTSB Form 6120.1/2, Pilot/Operator Aircraft Accident Report, by certified mail. The form was accepted but was not returned to this office at the completion of this report.