I’m a little bit piqued that the official site beat me to this posting at Charm School that goes into a LENGHTY analysis of the themes inherent in the title. Here’s a taste:
A JUNGIAN VIEW -
Imagine the story as a dream. The plane (a vessel of our direction and travels as a culture), is soaring at high altitudes (lofty ideals and, additionally or alternatively, our consuming desire for rapid success). The snakes Grendel about (monster figures are shadow figures, unintegrated parts of the self) the cabin, terrifying the passengers (citizenry). FBI agents (investigators probing the shadow - ideally, they are truth seekers) Samuel Jackson (hero, also the Law) and his partner (one white, one black - mythically this pairing is potent as a coupling of opposites. One might read in a peculiar function of race here, but there I won’t delve. Read Toni Morrison’s essay, Playing in the Dark, for a literary analysis. Draw your own conclusions.), escort incognito (more shadow and unrule, though he’s an innocent) witness (truth teller - here’s another duality, concealed truth - only the shadow knows), whose presence on board summons the snakes. The FBI pair are the best hope for resolution, to avert the “fall” ( avoid the ‘fatal retribution’ of hubris), or anomie (break down in social order, as well as personal unrest)
This is just a short excerpt, you’ll be reading for an hour if you really dedicate yourself to it. Enjoy.

Sometimes
SNAKES ON A PLANE
Are just
SNAKES ON A PLANE.
( Ghost of Sigmund Freud )