Licensed private pilot with 24 years experience witnesses three bright white cylindrical objects flying in perfect triangle formation during approach to Jacksonville International Airport on JetBlue flight. Objects were 20-25 feet long, completely smooth with no wings, rotors or exhaust. Encounter lasted 10-15 seconds at 2,800 feet altitude. Pilot contacted control tower and Naval Station Mayport to report the sighting. NUFORC considers witness exceptionally capable and credible.