What year did flying foxes become extinct?

Flying foxes as a whole are not extinct. There are more than 50 extant species of "flying foxes" still alive and flitting about all over the world - as well as several "fruit bat" varieties that belong to the same Genus Pteropus.

There are several flying fox species that are apparently now extinct:

The Percy Island Flying Fox (aka Dusky Flying Fox) is listed as Extinct because it has not been found in its only known range, or nearby, much after the original collection date despite extensive surveys. Note that The taxonomic status of this species is unclear. While some experts believe that the species is distinct from all other Australian Pteropus species, there has been speculation that the single specimen might in fact be a vagrant of another species.

The Large Palau Flying Fox (aka Palau Flying-fox, Palau Fruit Bat) is listed as Extinct because it has not been recorded since prior to 1874, and extensive surveys over the years have failed to locate this species.

The Lesser Mascarene Flying Fox (aka Small Mauritian Flying Fox, Dark Flying Fox) is believed Extinct. The last authentic record of this species on Mauritius was in 1859, but it is believed to have died out between 1864 and 1873. On RĂ©union, no new records appeared after 1862 and it seems probable that it became extinct in the 1860s.

The Guam Flying Fox (aka Guam Fruit Bat) is listed as Extinct because it has not been recorded with certainty since 1968, and intensive surveys of fruit bats on Guam in intervening years have failed to locate this species.

The Small Samoan Flying Fox (Pteropus allenorum) is a species of fruit eating megabat whose type specimen was originally collected in Samoa in 1856, but was not identified as a new species until 2009. As the type specimen is dead, and no other examples of the species are known, it is believed to be extinct.

The Large Samoan Flying Fox (Pteropus coxi) is a species of fruit eating megabat whose type specimen was originally collected in Samoa in 1856, but was not identified as a new species until 2009. The only known specimen was collected by an American expedition to Samoa in 1838-1842, It was rediscovered by Smithsonian mammalogist Kristofer Helgen preserved in alcohol. It was the largest known bat from Polynesia. As the type specimen is dead, and no other examples of the species are known, it is believed to be extinct