The 'Natter' Project was one.
The Natter was a vertical take-off interceptor, designed to blast up into an oncoming bomber stream (somewhat like a manned surface-to-air missile). Here's how:
The Natter would be standing against a launch tower, nose pointed skywards. Its pilot would press the start button, thus firing the main rocket. A second later he would switch to full power, the Natter being held in position on the tower by a brake. The ground crew would then ignite four powder booster rockets by hand, using a burning wick on the end of a long bamboo cane (!!!). When all motors were burning for at least 10sec., the brake would be released. The Natter would then leave the launch pad at 800km, controlled from the ground for the first 1.5km and, once the powder rockets had burnt out, control would be handed over to the pilot.
He would then find the biggest concentration of Allied bombers and head towards them. Pressing the firing button would set off several functions at once. A plexiglass cover over the missiles would fall away, and they would fire altogether in a staggered salvo towards the oncoming bombers, like a shotgun effect. At the same time the rocket motor would detach and return to earth on a paracute, to be retrieved and used again. The pilot would also return using an automatic parachute. The rest of the aircraft was made of cheap wood construction and would be lost after the flight. In theory.
Today in history, on 1st.March 1945, the first manned rocket-powered Natter blasted off from the Heuberg Military Training Area near Bachem. After 55sec., it exploded, killing its pilot Lt.Lothar Seiber. He became the first man ever to take off vertically from the ground under rocket power. Parts of his body were later found in a crater 7km away.
As the Allied armies were closing on Bachem, the project was cancelled...four Natter aircraft fell intact into enemy hands, three to US and one to the Russians.
If the Natter had been successful, could it have reversed the war? Not a chance, given how far the Allies had advanced. However, the somewhat nutty Natter makes for an interesting WWII postscript...