A developer presumed dead with his wife in a private plane crash near Jamaica had an "uncanny instinct" for revitalizing properties and an "incalculable" impact on his western New York hometown's resurgence from crumbling industrial center to trendy destination for young professionals, friends and colleagues said.

Laurence Glazer, 68, bought up dozens of properties in Rochester, on the shores of Lake Ontario, including landmark buildings belonging to the manufacturing giants Xerox Corp. and Bausch + Lomb. He converted abandoned factories into loft apartments and turned a shuttered hospital into offices.

Glazer had a way of "taking properties that were dead and breathing life back into them at a time when people were really skeptical about the ability to do that," Heidi Zimmer-Meyer, president of Rochester's Downtown Development Corp., said Saturday.

The U.S. Coast Guard said Glazer and his wife Jane were on a single-engine turboprop Socata TBM700 that flew on its own for 1,700 miles before running out of fuel and slamming into the sea off Jamaica's northeast coastline. The couple apparently was incapacitated.

Rescue crews said Saturday they could no longer see debris spotted Friday evening by a military aircraft drifting roughly 24 miles off the coastal town of Port Antonio in a stretch where the water is up to 6,500 feet. A 154-foot U.S. Coast Guard cutter and a helicopter crew aided in the search Saturday.

"We would have to assume it may have sunk," Jamaica Coast Guard Commander Antonette Wemyss-Gorman said.

Laurence and Jane Glazer, the founder of household-products catalog company QCI Direct, were both experienced pilots. They were flying to Naples, Florida, near where Glazer's development company, Buckingham Properties, also has interests.

"It's beyond tragic here. We're reeling," Zimmer-Meyer said, calling the couple "people who just cannot be replaced."

Gov. Andrew Cuomo, Lt. Gov. Robert Duffy and Sen. Charles Schumer were among the officials who publicly expressed sorrow for the couple's loss.

Duffy, the former mayor of Rochester, said the Glazers "possessed two of the brightest minds in business."

Air traffic controllers were last able to contact the pilot of the Glazers' plane at 10 a.m., about 75 minutes after it took off from the Greater Rochester International Airport.

Fighter pilots sent to shadow the plane saw its windows frosting over and the pilot slumped over but breathing. One of the fighter pilots speculated that the Socata pilot was suffering from hypoxia, or oxygen deprivation.

Cases of unresponsive pilots are unusual and often attributed to insufficient cabin pressurization that causes the pilot to pass out, aviation safety expert John Goglia said. A 1999 Learjet crash that killed professional golfer Payne Stewart and five others was attributed to cabin depressurized that caused all aboard to lose consciousness.

Harold Samoff, the lawyer who recruited Glazer to real estate from working for his wife's family's printing company in 1970, said his friend was a "man of many, many, many skills" who had an interest in "practically everything."

"Once he got involved, he knew it," Samoff said.

Glazer and Samoff started with a small apartment building, around the start of the city's long economic decline, and went on to acquire and revitalize more and bigger properties on the periphery of the city's core, reasoning that "just like blight can spread, improvement can spread, also," Samoff said.

"His contribution is actually incalculable because a lot of other people didn't step up" to refurbish buildings as early as he did, Samoff said.

Glazer was also generous with advice to others just starting out, Zimmer-Meyer said. She said she received a call last week from a young real estate entrepreneur who mentioned that Glazer had helped her.

"The one good thing is that he's left an unbelievable legacy," Zimmer-Meyer said. "The difficult thing is that he's gone."