Roy Batson tends the cloud-making machine behind the outfield wall during opening day for the Los Angeles Angels. There’s just one downside to the bubble clouds: “We can’t have any control over where they go,” Batson says.

ANAHEIM, Calif. — On opening day at Angel Stadium, as baseball players stretched on the grass, an unassuming “A” with a halo took flight from behind the outfield wall.

A few Angels pointed at the team’s logo as it drifted higher. The ushers watched with arms folded. A few seconds later, up floated another.

Behind the outfield wall, Roy Batson stood chuckling Monday as the machines in front of him spit out a new form of advertising: bubble clouds. Created by Snowmasters, an Alabama special effects company, they’re the latest effort by marketers to grab people’s attention.

The machines took a bubbly liquid, mixed it with helium, then cut it into 2- and 3-foot-wide clouds the shape of the Angels logo. The team added them to promote its own brand along with the beer, phone and gasoline companies whose messages are scattered throughout the stadium.

Snowmasters calls the clouds “Flogos,” flying logos. It has released them in the shape of golden arches at a McDonald’s-sponsored event in Las Vegas, the number “207” for a Hard Rock Hotel in San Diego (207 is the hotel’s street address) and an “S” for Sheraton Hotel and Resorts in New York.

“In today’s economy, everybody’s looking for something different,” said Batson, head of Snowmasters’ West Coast operations.

Advertisers are trying lots of ways to target people who fast-forward through TV commercials and ignore print ads. In the last year or so, companies have paid consumers to put ads on their eyelids and to wear branded T-shirts every day of the year. A Florida school district even sold advertising space on its report cards to McDonald’s, and a classroom in Idaho imprinted every handout with a local pizza shop’s logo.

But the sky’s the limit, it seems, on ads in the air.

“It’s unmarked; it’s unblemished,” said Steve Hall, editor of AdRants, an industry Web site. “Mostly, when you look up you see birds.”

There have, of course, been ads in the sky for as long as the technology has existed to put things there. Hot-air balloons and blimps often display logos, and it’s hard to go to the beach in the summer without seeing an airplane towing a banner urging you to watch, drink or buy something. Airlines have picked up on the idea of ads in the sky, painting logos on their planes and also slapping them on tray tables, overhead bins and even air-sickness bags.

Snowmasters came up with the idea for Flogos in 2001 and, after refining the process, decided it was finally ready eight months ago. The medium has proven so popular, Batson said, that the company has opened eight offices globally in the last year. That’s during a time when overall advertising spending has slowed, by 1.7 percent in 2008, and is predicted to decline 6.4 percent in 2009, according to industry forecaster Jack Myers.

Flogos isn’t the only company trying to take advantage of the wide-open spaces to push products.

Business is also booming for Skytypers, its executives say. The Las Vegas company recently patented a technology that uses five airplanes to make dotted clouds that spell out messages two miles high.

“With media and technology and the economy, all three are driving people to go outside the box and try different things,” Skytypers President Stephen Stinis said.

Each Skytypers letter is the size of the Empire State Building (more than 1,200 feet) and the messages are 5 to 7 miles long, he said. He says messages can be seen as far as 15 miles away.

Cloud ads such as these appeal to advertisers because they can reach masses of people in ways that other media can’t, Stinis said. People may be watching less TV or browsing many Web sites, but they all look up from time to time.

“In four hours, I can pretty much saturate the whole market,” Stinis said.

Clouds and other quirky types of advertising also attract young people, an elusive demographic often cynical about marketers’ attempts to reach them. When the University of California, Riverside, opened a new student center, it released Flogos shaped as the school’s initials and its logos: sunbursts and bears. Todd Wingate, the director of the student center, said the clouds attracted students from all over campus.

“It draws your attention right away,” said Josh Leal, 19, a student who attended Monday’s Angels game and wandered to the outfield wall to investigate the clouds. “It’s pretty cool,” he said.

Not everything is bright and sunny in the world of cloud advertising.

Hall, of AdRants, warns that many advertising trends such as cloud advertising are merely flashes in the pan: Slapping ads on houses or people’s foreheads or on rooftops so that people can see them from a plane, for instance, haven’t stood the test of time.

“Increasingly, when nothing is working, companies think when the next new thing comes out, they might as well try it,” he said.

Some environmentalists worry about the chemicals that make up the 1 percent of Flogos and how they may affect the climate. Batson says the product is environmentally friendly because it’s made of water and materials from plants.

Plus, cloud ads may run into problems that print or TV ads don’t, such as weather. At the Angels game, wind gusts of 19 mph tore some of the Flogos into unintelligible cloud pieces, and the sun melted others.

Chad Haberstroh, a 29-year-old film editor, said he had to ask an usher what the Flogos were supposed to be because some of them were coming out as blobs. Others floated into the sky and were too small to see, he said.

“We can’t have any control over where they go,” Batson admitted as he watched one drift over the parking lot and away from the park.

Still, the cloud companies aren’t ready to cede their new advertising medium to nature just yet. Flogos and Skytypers are looking into colored clouds to draw more attention, and Flogos has floated the idea of neon clouds that are visible in the dark.