Answer:

hopin

Answer	Crossword Clue
HOPIN	"There's a seat for you!"
HOPIN	Driver's invitation
HOPIN	"I'll give you a lift"

HOPIN	Invitation to a hitchhiker
HOPIN	Invitation to a hitcher
HOPIN	"Climb aboard!"
HOPIN	Words to a hitcher
HOPIN	"Come on, let's go for a ride!"
HOPIN	Pickup line?
HOPIN	"Climb aboard"
HOPIN	Welcome words to a hitchhiker

HOPIN	Words to a hitchhiker
HOPIN	Hack remark
HOPIN	Hack's remark
HOPIN	Music to a hitchhiker's ears
HOPIN	Shout to a hitcher
HOPIN	Welcoming words from a driver
HOPIN	Cabbie's invite
HOPIN	Words to a hitchhiker, and a literal hint to what spans both words of the answers to starred clues

HOPIN	Words to a hopeful traveler
HOPIN	Welcome words, to a hitchhiker
HOPIN	"Sure, I'll give you a ride!"
HOPIN	Offer to a hitchhiker
HOPIN	Ride invitation
HOPIN	Roadside offer
HOPIN	Welcome words to a hitchhiker.
HOPIN	Jump aboard.

HOPIN	Invitation to a hitch-hiker.
HOPIN	Invitation to a ride.
HOPIN	Invitation to a ride
HOPIN	Invitation from a motorist
HOPIN	Join for a ride
HOPIN	"I can give you a lift"
HOPIN	Cabbie's cry
HOPIN	"Let's go for a spin!"

HOPIN	Cabbie's call
HOPIN	Cabbie's line
HOPIN	Words said through a car window