Emily said drive-in movies used to be common.
"Some people may want to relive an old experience and younger people may want to experience something new."
The girls said the amount of positive feedback and support they had received so far showed it was an awesome decision.
The main aim of the evening was to raise funds for the Cancer Society with the event being cash only.
"We really wanted to get behind it so we decided we would just focus locally and support the Whanganui Cancer Society Branch," Catherine said.
The girls have spent the past few weeks selling firewood and raffle tickets at local markets to gather funds to pay for a popcorn and candy floss stall, hot food truck and a coffee and icecream cart.
From there they have sold more than 100 tickets to those wanting to bring a deck chair and blanket and have 50 reserved parking spots for those into the more traditional park-up vibe, some of whom will be turning up in old hotrod cars.
The 16-year-olds are hoping the night will be a lot of fun by bringing a "historic" event back to life with the film streaming on a Panasonic cinema projector.
"We are hoping that by the end of the night people have relived an old memory or have experienced something they've only heard about or seen in the movies," Emily said.
• Gates open at 5.30pm on Saturday with the movie kicking off around 6.30pm with tickets and parking spaces still available.