Undated (AP) _ Airports in the Northeast corridor reported curtailed service today in advance of Hurricane Gloria, while Amtrak put on extra cars to accommodate stranded travelers, officials said.

Spokesmen for airports from New York to Boston said service could be shut down altogether if winds rose to dangerous levels.

The Port Authority of New York and New Jersey said all three metropolitan airports - John F. Kennedy International, LaGuardia and Newark International - were open but operating in ''limited volumes.''

Many airlines, including People Express, U.S. Air and American Airlines, canceled some flights and rerouted others, said PA spokesman Mark Marchese.

He said the Federal Aviation Administration would make the decision to close the airports if and when winds reached dangerous levels. Until then the airlines had the option of canceling or rescheduling flights.

In the Washington area, both Dulles International Airport and National Airport reported curtailed service. Eastern Airline shuttle flights from Washington to New York were canceled as no incoming or outgoing flights were reported in the first hour of National's operations today.

Charles Budley, assistant air traffic manager at Baltimore-Washington International Airport, said flights seemed to be about 60 to 75 percent normal. There appeared to be a decrease in commuter flights, which use smaller planes, he added.

In Hartford, Conn., Bradley International Airport Manager Robert Juliano said the airport remained open at midmorning and all flights were taking off as scheduled.

Ten flights took off as scheduled from Rhode Island's T.F. Green Airport in Warwick, but a half-dozen flights, primarily headed for LaGuardia and Washington, D.C., were scrubbed, said Anthony Rosati, assistant state director of transportation for airports.

''We're not going to expect many more inbounds from East Coast points, and I imagine from any point. I wouldn't want to see any aircraft here when that storm arrives,'' he said.

Logan International Airport in Boston was open and planes were departing, said a man, who would not give his name, in the operations department of the Massachusetts Port Authority, which operates the airport.

He said he had been told that Peoples Express was not flying and that Eastern Airlines and New York Air had canceled flights only to LaGuardia Airport.

Amtrak officials in Washington said trains in the Northeast corridor were running on schedule and additional cars would be put into service later today to handle passengers unable to travel by plane.

''We have no delays and expect no problems in the forseeable future,'' said Amtrak spokesman John Jacobsen.

''We have plans to put extra equipment in operation for people who find it difficult to take other transportation.''

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