The storyline of the film is credited to the University of Pittsburgh administrator--and first time Hollywood writer--Dalessandro, who got the idea in 1992 from a nature magazine. "I read about the Indonesian brown tree snake climbing onto planes in cargo during World War II". He originally wrote the screenplay about the brown tree snake loose on a plane and called it "Venom". He soon revised it to be about poisonous snakes, and then crediting Alien revised it again to include "lots of them loose in the fuselage of a plane." [1]
Dalessandro's third draft of "Venom" was turned down by all 30 Hollywood studios in 1995 and the Pittsburgh administrator lamented "My big foray into Hollywood. They put it on a shelf." In 1999 though a producer for MTV/Paramount followed up before NewLine took over.
SNL skit: February 1998.
Cliffs: Snakes on a Plane story written 1992
SNL skit 1998.
Snakes on a Plane NOT based on SNL skit.