There *are* actually multiple women in this movie, but the ones other than Emma MacNeil are:
* an unnamed cabin attendant on the plane that gets bitten by the flying shark, and
* a character on the same plane simply titled Airplane Hottie, which should count as Minus One.
However this movie passes the interspecies Bechdel test, where two non-humans (a shark and octopus) get together and interact (fight) without mentioning humans.
That's as close as it gets.