Ju-87
The Junkers Ju-87 Stuka was a German dive bomber, extremely effective in the blitzkriegs of 1939 and 1940, but too slow to survice in the Battle of Britain. It was, however, quite accurate when it could deliver bombs in a near-vertical dive; it served out the war as an antitank and close support aircraft. The Ju-87 had a crew of two: a pilot and rear gunner; one of its unique features was a mechanical but automated device to pull it out of a dive even if the pilot blacked out from gravitational force.
As are many ground support aircraft, it would win no beauty contests. It had fixed landing gear at a time when streamlining was both an attractive and necessary feature of new aircraft designs. Some later versions were upgunned to carry two underwing, forward-firing 30mm antitank autocannon, which was useful on the Russian front. Compared, however, to the Soviet antitank aircraft, the Il-2 Stormovik, it lacked armor and survivability features. Nevertheless, it could be a fearsome tank killer. The highest Nazi combat decoration was the Knight's Cross of the Iron Cross, but it came with additional features to recognize special heroism. The only Knights Cross ever awarded with Oak Leaves, Swords and Diamonds went to Stuka pilot Hans-Ulrich Rudel, who claimed in excess of 500 Soviet tanks and a battleship.
Especially against civilians and inexperienced troops, the Stuka had a potent psychological weapon: sirens and whistles, activated by the speed of a dive, would scream as it dove; the sound was unforgettable. With experienced troops, it guided them in aiming anti-aircraft artillery. Eventually, it was replaced by ground attack versions of the Fw-190 fighter, which could defend itself against other airraft.