If cramped subways have you down, one real estate industry executive says he has an idea that will have you floating on Cloud Nine.

Dan Levy, president and founder of real estate website CityRealty, is going to pitch the East River Skyway, a system of gondolas to get people on the ever-developing Brooklyn and Queens waterfronts in and out of Manhattan, at a real estate summit today.

Levy estimates gondolas today can move 5,000 people an hour per direction, with cars that can fit up to 38 people and would arrive once every 30 to 40 seconds. The closest thing to a gondola New Yorkers have experienced here is the Roosevelt Island tram, which moved 2.6 million people in the last fiscal year.

"A lot of cities around the world have started implementing these because the technology for gondolas has changed substantially in the last 15 years," Levy told amNewYork. "They've gotten faster, they're higher capacity."

In his proposal, Levy envisions three phases -- each costing $75 million to $125 million -- that would run from the Brooklyn Navy Yard to Williamsburg then across the river to the Lower East Side; up to Greenpoint and Long Island City, then to Roosevelt Island and the United Nations; and from the Navy Yard to DUMBO and South Street Seaport.

Levy said the system could run through a private company or be operated in a public-private partnership.

"I think it can be built largely or perhaps entirely with private funds," he said.

Levy, a Williamsburg resident, came up with the proposal after taking a gondola during a ski trip in the Alps two and a half years ago. His proposal includes photos of gondolas used in London, Singapore, Chile and Germany.

He thought the gondolas would be an efficient way to serve people along a waterfront that is still being developed and will attract residents who are mostly going into Manhattan.

"I think the demand will be there," he said.

Sarah Kaufman of the NYU Rudin Center for Transportation said gondolas would be "fast and scenic" but would have to bring riders inland.

"And I don't see New Yorkers allowing this infrastructure to interfere with their skyline views," she said. Still, she said, "I hope we see some more infrastructure ideas from real estate companies in the future -- when they bring people to a neighborhood, they should be thinking about how to get them around."