1903 in aviation

January
January 1 Konstantin Tsiolkovski deduces the Basic Rocket Equation in his article Explorations of outer space with the help of reaction apparatuses.

February
February 16 Traian Vuia presented to the Académie des Sciences of Paris the possibility of flying with a heavier-than-air mechanical machine and his procedure for taking off, but it was rejected for being an utopia, adding the comments: The problem of flight with a machine which weighs more than air can not be solved and it is only a dream.

March
March 31 - Richard Pearse is reputed to have made a powered flight in a heavier-than-air craft, a monoplane of his own construction, that crash lands on a hedge. This date is computed from circumstantial evidence of eyewitnesses as the flight was not well-documented at the time. The machine made a flight claimed to be around 150 feet (45 m) on his farm at Upper Waitohi, near Timaru in south Canterbury, New Zealand.

May
May 11 - Richard Pearse is claimed to have made a flight of around 1,000 yards (900 m), landing in the semi-dry bed of the Opihi River.

August
August 18 - Karl Jatho makes a flight with his motored aircraft in front of four people. [1]. His craft flies up to 200 feet (60 m) a few feet above the ground in a powered heavier-than-air craft.

October
October 7 - Samuel Langley conducts the first tests of his full-sized man carrying version of his earlier model aerodromes. The pilot Charles Manly nearly drowned when the machine slid off its launch aparatus atop a houseboat and fell into the Potomac River.

November
November 12 - The Lebaudy brothers make a controlled dirigible flight of 54 km (34 miles) from Moisson to Paris, France.

November 19 Léon Y. K. Levavasseur demonstrates his Antoinette engine, designed as a lightweight powerplant specifically for aircraft.

December
December 8 - second attempt by Charles Manly to fly Langley's repaired full-sized aerodrome. As with the October 7 attempt the machine failed to fly tripping on its launch gear and somersaulting into the Potomac River nearly killing Manly. A surviving photograph captures the machine upended on its side as it falls off the houseboat. Langley himself was absent at this attempt but the machine's failure to fly ended his government(aka U.S. Army) funded attempts at building a successful full sized man-carrying flying machine.

December 17 - The Wright Brothers make four flights in their Flyer at Kitty Hawk, North Carolina following years of research and development. Orville Wright takes off first and flies 120 ft (37 m)in 12 seconds. This is frequently considered the first controlled, powered heavier-than-air flight and is the first such flight photographed. On the fourth effort, Wilbur flies 852 ft (260 m) in 59 seconds.