Power has been restored to the two LaGuardia Airport terminals that suffered outages earlier Tuesday due to the heat wave gripping the city.

Several flights had to be cancelled and others delayed because of the outages at the airport’s Marine Air Terminal, also known as Terminal A, which services Delta Airlines, and its Central Terminal building, which services American Airlines.

Electricity came back at the Marine Air Terminal around 3:00 this afternoon, and the Delta Shuttle resumed all flights at 4:30 p.m., with delays.

Full power was restored to the Central Terminal building shortly before 6 p.m., but American Airlines is still experiencing residual delays after offering only limited service in and out of LaGuardia most of the day Tuesday.

Port Authority officials say Con Edison experienced troubles with some of the utility's feeder cables. The power outage began Monday night, but was believed to have been fixed overnight, until problems persisted Tuesday morning.

Some passengers who missed their flights were bused to other area airports. Several American Airlines flights were also diverted to JFK and Newark airports.

Passengers traveling on either airline are advised to call ahead if headed to the airport to check on any cancellations or delays.

Travelers affected by the power outages have experienced delays because they were handed their luggage on the tarmac since the baggage carousel was down, and security checkpoints were running on a backup generator.

"I missed my flight," said one traveler. "Now I got to change my flight. And things ain't good."

"We're getting different reports that the flights are being cancelled or delayed but we really don't know," added another. "We're going to find out now but we're going to have to wait on line for an hour to get an answer."

"I'm definitely not happy about it," added a third. "I'm looking for new plans."

Meanwhile, service is back up and running again on the 1, 2, and 3 subway lines after a morning power glitch knocked-out service through most of Manhattan, possibly due to the city's heat wave.

Transit officials say they aren't sure if the outage was due to the hot weather, but they say a power problem knocked out a signal at the Times Square station earlier Tuesday morning. That caused a ripple effect that took down subway service from 137th Street all the way south.

About 10 trains were stuck in tunnels for about an hour, and scores of commuters were delayed or stranded.

"The trains ain't working and I can't even get back home because the train ain't working to go back downtown, or uptown, so I don't know where to go. I'm stuck right here," said one commuter.

"They just told us they had signal problems on the train and now everybody has to get off the train,” added another. Some people were upset. Some people are upset, but you just got to deal with it."

Transit officials say the trains stuck in tunnels did not lose lights or air conditioning.

With a forecast high of 101 degrees fahrenheit for Tuesday, the State Health Department issued an air quality advisory for all five boroughs, as well as Long Island and the Hudson Valley.

Officials are advising anyone with respiratory problems to stay indoors and in air conditioning. The advisory is in effect until midnight.

With air conditioners running at full blast, Con Edison says its power grids in northwest Queens are stressed.

Con Ed says the heat is causing problems with its feeder cables in the area, and the utility is asking people to conserve power by not using non-essential electrical appliances and equipment.

The heat may have contributed to some power outages in other parts of Queens, too. Con Ed asks people who live in Long Island City, Sunnyside, Woodside, Hunters Point, and Astoria to be especially aware of the potential for outages.

Non-essential appliances include air conditioners, washers, and dryers. Con Ed also urges customers to turn off lights and televisions when not in use.

The utility says Monday's usage throughout the entire city was the second highest on record.

Mayor Michael Bloomberg says it's important all New Yorkers do their part to conserve energy. Even at City Hall, some lights were shut off Tuesday.

"Use air conditioners only when you are at home,” said the mayor. “Running an air conditioner when you're not there, it may be cool when you get back, but it also may help create a power outage and then there won't be anything when you get back."

In a NY1 Snap Poll Tuesday morning, 71 percent of New Yorkers insist they'll do their part to reduce the load on the power grid.

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