The milblog War Is Boring has produced two articles about unconventional, odd and weird incidents where aircraft were shot down or destroyed in unusual circumstances. Here are a couple of excerpts from the second article.
March 1943: U.S. Army Air Corps parachutist versus Japanese Zero
2nd Lt. Owen Baggett was the co-pilot of an Army B-24 bomber sent to bomb Japanese facilities in Burma. Their plane shot nearly to pieces by Zero fighters, Baggett and four other crewmen bailed out. The Zero pilots made sport of the parachutists, machine-gunning and apparently killing two of them in mid-air.
Enraged, Baggett—still dangling from the silk canopy presumably thousands of feet in the air—drew his .45-caliber pistol and fired at a passing Zero. The Japanese plane stalled and crashed. Later, while a prisoner of the Japanese, Baggett learned that he had hit the Zero pilot in the head, killing him.
1948 & 1949: Royal Air Force Spitfires versus Israeli Spitfires versus Egyptian Spitfires
During skirmishes in the Middle East in 1948, the armed forces of Israel, Egypt and Great Britain all used pretty much the same models of Spitfire fighters, leading to fatal confusion.
British forces were pulling back from Palestine, leaving Egypt and the new state of Israel to fight it out over territory claimed by both Jews and Arabs. In May, waves of Egyptian Spitfires attacked the airfield at Ramat David, believing it to be held by Israel.
But in fact, British troops were still in charge of the base. The Egyptian planes unwittingly destroyed two Royal Air Force Spitfires and two transport planes and killed four men. With help from gunners on the ground, surviving British fighters destroyed five Egyptian Spitfires.
And after weeks of chaotic combat on three sides, in January 1949 two RAF Spitfires mistook two other RAF Spits as Israeli planes and shot them down, too.
There's more at the link, and in the first article in the series. Interesting reading for aviation buffs.