"There's not enough income in it or else you'd see AMC or others getting drive-ins," Vogel said. "It's hard-earned money."
Today some 400 drive-ins remain in the United States, a number that has not changed much in the past five years. Another 100 drive-ins exist outside the United States, mainly in Canada and Australia. Kopp said the concept is suddenly becoming popular in China.
More than 75 percent of the drive-ins in this country are privately owned small businesses, according to the National Association of Theatre Owners.
"Digital cinema will be both an opportunity and a threat for drive-in owners," said the association's director of media and research Patrick Corcoran in an e-mail. "An opportunity because digital will allow them to get new movies sooner than they do—they are often weeks behind the break for new films. It's a threat in that the digital transition will be expensive to manage, and some may not be able to do it."
Kopp of course bets on the drive-ins' survival. In 2005, he and his wife bought the Raleigh Road Outdoor Theatre in Henderson, N.C., for $22,000 on eBay. He said they've invested about $300,000 since to clear the seven acres of weeds and modernize the technology. Today the theatre can accommodate 265 cars and show movies in a 60-foot-by-80-foot screen. The sound comes through car radios.
Film fare of the Raleigh Road and other drive-ins typically consists of G-rated films, Kopp said. Disney movies thrive, as do animated films.
"We've had some folks that come out on a weekly basis. It's almost like a tailgate party," Kopp said.
He's seen his share of fogged-up windows too, including a middle-aged couple too "passionately involved" to notice that the theatre's lights were off and gates were locked.
And then there are the people who sneak in without paying.
"Last week we were patrolling the property in the golf cart, and we saw a hole in the fence," Kopp said. "Some kids had been running through. So we put some chairs up and some popcorn out and left a sign that said, ‘At least sit down and watch the movie.' We were kids once too."