When Air nightclub breezed onto the grounds of the Ronald Reagan Building last summer, Brandon Spooner thought it was the greatest thing to hit the city.

It was a "white-hot good time," he says. "A sea of beautiful people of all races, backgrounds and cultures. Partying under the stars with my friends and unwinding through a range of musical genres -- calypso, soca, salsa -- blended with the hottest R&B, hip-hop, Chicago house, and the list just can go on."

Spooner, a 28-year-old pretrial services officer from Baltimore, was one of many black professionals who went to the club at the invitation of a black Web-based promoter, Flow Entertainment Group, which helped the crowd tilt slightly toward black professionals on Fridays. The Saturday night events used a diverse array of promoters and a similar music format, but there weren't as many black patrons.

Spooner couldn't wait until this season began. But when he showed up on a recent Friday night, he was sorely disappointed. The cashiers were telling patrons that Air was no longer playing hip-hop; instead, a deejay played house and techno music. They distributed fliers announcing that Fridays would now be "St. Tropez" nights. Flow was out as a promoter.

"The vibe was not the same," says Spooner. "You didn't get that all-inclusive kind of feeling."

Several in the crowd -- "too many to count," says Air cashier Nathalie Bourdereau -- demanded and got refunds.

In the days to come, Flow announced the change to the 100,000 subscribers, mostly African American, to its Web site. "Last week, we were surprised to learn that the operators of the Reagan Building want to go in a different direction," the message said, explaining the new music format and saying that they won't be involved with the party. "It is sad to see that even in 2004, the struggle continues."

Several Flow subscribers didn't take the news well.

"I was ticked," says Sy Penn, a 29-year-old advertising executive who wrote Flow to say she would no longer patronize Air. "To be honest with you, it's quite obvious. It doesn't take a rocket scientist to figure out that we are being bused to the other part of town. Slowly but surely, they are just moving us out."

Trade Center Management Associates, the company that leases the private space in the Reagan Building and which operates Air, got dozens of outraged e-mails about the change, says marketing manager Howard Kitrosser.

Giles Beeker, a vice president at Trade Center Management Associates, says the changes had nothing to do with racism. "Nothing could be further from the truth," he says, explaining that the new format was instituted mostly for economic reasons. While Friday and Saturday nights drew the same number of people, the bar and food receipts generated by the Friday crowd were less than those on Saturday, he says. He declined to provide exact figures, saying Trade Center Management Associates is a private company.

Beeker says Air advertised through Flow, but it wasn't cost-effective, given the number of people Flow brought in. "Flow doesn't have the exclusive on African American patrons," he says.

He doesn't want the crowds to tilt one way or another racially. "Our goal at this club has never been to have a black night or a Latino night," he says. " . . . We want to make sure a few vocal people in the crowd don't turn the music one way or the other."

Diversity, Beeker says, is part of the mandate coming from the federal government, which owns the property and agreed to allow the Air parties, and a now-defunct concert series, as part of a push to breathe new life into downtown. "We've always tried to make this a club that was appealing to everyone," Beeker says. "It looks like a cross section of America. . . . We've never tried to make it definitively one [race] per night."

From the start, it was an experiment in multiculturalism that was daring in Washington's segregated club scene, say many of the promoters who were involved with creating the events. "It was like integration 1954," Keir Gumbs, one of Flow's owners, told a reporter earlier this summer in an interview leading up to Air's second season.

In a joint interview with Flow before the change, Kitrosser said: "We are both looking for upwardly mobile people who are out to have a good time."

"We did a fantastic job introducing Air in 2003," said Al Flowers, another co-owner of Flow. "Branding the nights 'Friday at Air' and the expectations at Air. Just the marketing we did to over 15,000 registered members into our 'Air Friday' database. We are going to have to steer them elsewhere."

Until two weeks ago, Andrea Skarupski was Air's VIP coordinator, in charge of bringing in celebrities. But she says the way the format was changed was an affront to her black clients.

They "might as well have started playing country music, it was so obvious," she said. "I saw what was going on. I didn't want to be associated with this. I'm a white female and this is wrong. It's blatantly racism."

She quit on the night that patrons were informed that hip-hop wouldn't be played anymore, she says, to save her reputation. "I had people calling me saying, 'We're never going to come to one of my parties again,' " she says. "It's really hard to regain that confidence."

Julie High and Geoff St. Germain dance at Air, which discontinued hip-hop Fridays. "The vibe was not the same," says Brandon Spooner.Andrea Skarupski quit as VIP coordinator for Air after the format change. "I saw what was going on. . . . It's blatantly racism," she says.