On November 2, 2003, about 1130 eastern standard time, a Fleet 16B, N80656, was destroyed when it impacted water about 1 mile south of Fishers Island, New York. The certificated private pilot and passenger were presumed fatally injured. Visual meteorological conditions prevailed and no flight plan had been filed for the personal flight that departed the Westerly State Airport (WST), Westerly, Rhode Island, about 1100. The local flight was conducted under 14 CFR Part 91. The accident airplane was part of a flight of three airplanes, which included a Citabria, and an RV-8. The pilot of the Citabria stated he was performing formation flying with the Fleet, while a passenger in the RV-8 took photographs. The three pilots maintained radio communication with each other throughout the flight. About the time of the accident, the Citabria was the lead airplane. When the Fleet pilot did not respond to a radio call, the Citabria pilot circled back to look for the airplane, and noticed debris floating on the water. The pilot of the RV-8 stated he observed the yellow painted accident airplane at a very low altitude over the water. He did not clearly observe the airplane impact the water. He observed a brief flash of yellow, followed by a splash. A witness fishing on a boat stated he observed three airplanes. Two airplanes looked like they were performing in an air show. The airplanes appeared to be chasing each other, performing steep turns, steep ascents and "swooping down really low to the water." The witness stated that the accident airplane "buzzed" the surface of the water, entered a climb and descended toward the water. The airplane appeared be pulling up when it impacted the water. He described the impact as an "intense crash." He further described the engine noise prior to the impact as constant. He maneuvered to the accident site area and observed a fuel slick and some small broken wooden parts on the water. Another witness stated he observed two airplanes "very low" over the water, that looked like they were "dog fighting." The airplanes were performing tight circles, figure eights, and steep turns. He stated the airplanes were at an altitude of about 500 feet, and descended as low as a few "tens of feet." He also noticed a third airplane flying above the two other airplanes. The accident airplane "swooped down toward the water" at least twice and then climbed at a steep angle. He then observed the accident airplane enter a steep nose dive. The airplane appeared to be pulling-up and was at an angle of about 45-degrees when it impacted the water. The witness then observed debris floating on the surface of the water. The witness further stated that he did not hear any unusual engine noises prior to the accident. The airplane was equipped with a Kinner R-56 radial engine. A lobsterman inadvertently recovered a Kinner five cylinder radial engine, in the vicinity of the accident site, about 1 year after the accident. The engine was subsequently examined by a Federal Aviation Administration inspector. The engine was significantly corroded. All cylinders were present and did not display any obvious visual evidence of a catastrophic failure. The propeller remained attached to the engine; it was noted that both ends of the wooden propeller were splintered. As of the date of this report, no major portions of the airframe have been located. According to a mechanic who maintained the airplane, the most recent annual inspection was performed on March 16, 2003. According to the accident pilot's logbook, at the time of the accident, he had accumulated about 1,331 hours of total flight experience, which included about 160 hours in the accident airplane. His most recent Federal Aviation Administration third class medical certificate was issued on November 15, 2001. The weather reported at an airport about 7 miles north of the accident site, about the time of the accident, included clear skies.