What kinds of cars does Gatsby use to transport guests?
Chapter Three of The Great Gatsby opens with Nick describing the grand parties that his neighbor (Jay Gatsby) throws all throughout the summer. Whether Gatsby is having guests over to sun themselves on his beach and go diving off his raft during the day or to drink and dance relentlessly through the night on the weekends, there always seems to be some sort of wild, glamorous ruckus going on.
Thus, Gatsby's house is always buzzing with people coming and going. On Mondays, servants arrive to repair the damages from the weekend parties; on Friday, huge shipments of citrus show up to be juiced by the butler;and at least "once a fortnight," an army of caterers comes to setup immense buffet tables.
The most glamorous of these people--which is to say, the guest themselves--are transported to Gatsby's parties on the weekend by Gatsby's own Rolls-Royce and station wagon, both which go to and from the train station, ferrying passengers to the lavish celebration.
Gatsby uses a station wagon and a Rolls Royce to ferry guests to and from the train station. He employs these luxury automobiles as though they were common taxicabs or jitneys. His cavalier attitude toward these possessions is nicely paralleled in the scene where he shows Daisy his collection of shirts.
You'll find this answer at the start of Chapter 3. Gatsby used both his Rolls Royce and his station wagon to transport guests to his parties.
He uses the car, Rolls-Royce and his own station wagon to transport the guests to and fro, symbolizing of the importance of the American Dream, where people pursued material comforts in their daily lives, always choosing the luxurious objects to make them significant and important, rising up the social network.