I don't really know what year aerial torps were introduced.
I think experiments were held back in 1919...I think the Italians experiemnted with that, and not sure they were the first
According to that trusted source WIKI
In 1915, Rear Admiral Bradley A. Fiske conceived of the aerial torpedo.
The idea of dropping lightweight torpedoes from aircraft was conceived in the early 1910s by Bradley A. Fiske, an officer in the United States Navy. A patent for this was awarded in 1912. Fiske worked out the mechanics of carrying and releasing the aerial torpedo from a bomber, and defined tactics that included a night-time approach so that the target ship would be less able to defend itself. Fiske imagined the notional torpedo bomber would descend rapidly in a sharp spiral to evade enemy guns, then at an altitude of about 10 to 20 feet (3 to 6 m) would level off long enough to line up with the torpedo's intended path. The aircraft would release the torpedo at a distance of 1,500 to 2,000 yards (1,400 to 1,800 m) from the target. In 1915, Fiske proposed attacking enemy fleets within their own harbors using this method, if there was enough water (depth and expanse) for the torpedo to run. However, the United States Congress appropriated no funds for aerial torpedo research until 1917 when the U.S. entered into direct action in World War I. The U.S. would not have special-purpose torpedo planes until 1921.
First torpedo aircraft
Meanwhile, the Royal Naval Air Service began actively experimenting with this possibility. The first successful aerial torpedo drop was performed by Gordon Bell in 1914—dropping a Whitehead torpedo from a Short S.64 seaplane. The success of these experiments led to the construction of the first purpose-built operational torpedo aircraft, the Short Type 184, built from 1915.
An order for ten aircraft was placed, and 936 aircraft were built by ten different British aircraft companies during the First World War. The two prototype aircraft were embarked upon HMS Ben-my Chree, which sailed for the Aegean on 21 March 1915 to take part in the Gallipoli campaign.
Around the same time of the Royal Navy experiments, in Italy Captain Alessandro Guidoni of the Regia Marina was conducting similar trials since 1913, with the help of inventor Raúl Pateras Pescara, and in February 1914 successfully dropped an 800 lb torpedo, leading to disputes over which country first used an aerial torpedo.
If it ain't broke, don't fix it!