Answer:

stowaways

Answer	Crossword Clue
STOWAWAYS	Freeloading passengers
STOWAWAYS	The Marx Brothers, in "Monkey Business"
STOWAWAYS	The Marxes, in "Monkey Business"

STOWAWAYS	Some fare-beaters
STOWAWAYS	Certain passengers.
STOWAWAYS	Free riders
STOWAWAYS	The Marx Brothers in "Monkey Business," e.g.
STOWAWAYS	They didn't pay