During World War II in the Pacific the US Navy was faced with the threat of Kamikaze airplane attacks (as we all know). This article says those planes were old training planes of wood and fabric that were slower than the more modern Japanese fighter planes. This is important due to the fact that these planes were slower and for some reason more difficult for Navy gunners to shoot down. These planes were also more difficult to pick up on radar thus able to get closer to their targets before crews could react. Towards the end of the Pacific war the Kamikaze attacks were more of a problem than submarines. One of the last US combat ships to be sunk by Kamikaze attack was the USS Callaghan on 28 July 1945.
Source: "The sinking of the USS Callaghan" by Andreas Forrer, History Magazine Dec/Jan 2018.
In a book review in the same source (above) James Hamilton-Paterson reports on the US spy plane the SK 71 which could fly at 85,000 feet and at speeds three times the speed of sound. It appears the planes flew from 1964 to 1999 when they were made obsolete by satellites and the growing use of un-manned flight. The book title is "A History of Untouchable Spy Plane".
