New York Gov. Andrew Cuomo better watch out — the “bartender” is back.

The nascent opposition to Cuomo’s dream of building a $2 billion AirTrain to LaGuardia Airport just got a boost from one of the biggest political megaphones in the city, Rep. Alexandria Ocasio-Cortez, who helped scare off Amazon from a plan put together by the governor to bring the retail giant’s second headquarters to Queens.

The far-left freshman Democrat — who represents portions of western Queens — sent a blistering letter to the feds on Friday demanding more information about why the Port Authority of New York & New Jersey ruled out alternatives to Cuomo’s plan, including subway extensions and bus lanes.

“This decision will have a lasting impact on thousands of people in our community,” Ocasio-Cortez said in a statement. “The community must receive answers to their fundamental questions and it’s imperative that we understand why further investment and improvement of other transit options have been ruled out.”

Ocasio-Cortez’s opposition lends a powerful voice that helped to coalesce opposition to Amazon’s now-aborted plans to build a corporate campus in Long Island City. That defeat saw Cuomo flooded with more than 2,000 emails and letters chiding him over the loss of the $3 billion deal, including one that read, “You got outsmarted by a bartender,” alluding to one of Ocasio-Cortez’s prior jobs.

Still, it’s unclear how much impact she can have in this situation.

Her letter comes after the Port Authority — to which Cuomo appoints half the board — requested the feds back the proposal to build the $2 billion elevated tram, which would force riders to travel out to Willets Points near CitiField and then trek back to LaGuardia.

Willets Point is currently served by the 7 train and Long Island Railroad’s Port Washington branch.

Transit activists and neighborhood groups have stepped up their opposition in recent weeks to the project, citing its ballooning price tag — it was initially supposed to cost just $450 million — and backpedaling route.

And they’ve questioned its mass transit connections, pointing out the 7 train is already packed and the LIRR only runs trains to Willets Point every 30 minutes at peak. Cuomo has promised improvements to the LIRR service if the AirTrain is built.

“If we’re looking at this from a transit perspective, it’s a very dubious proposition for New Yorkers,” said Benjamin Kabak, a lawyer and noted transit activist who writes the Second Avenues Sagas blog. “It doesn’t help travelers get to the airport faster, it doesn’t help workers get to the airport faster.”

He added: “[AOC’s letter] could help bolster opponents’ arguments if they sue to stop the project because it highlights some of the deficiencies in the FAA’s review process.”

The Port Authority backed Cuomo’s AirTrain plan in October 2018 and the FAA signaled its inclination to follow suit in a November 2019 presentation, leaving residents with few options — save lawsuits — to slow the project down.

Advocates, like Kabak, argue the Port Authority wrongly rejected potential alternatives like extending the subway from Astoria; building an AirTrain to the Jackson Heights heights subway hub, which is served by the E, F, M and R trains; or giving the current bus service to LaGuardia dedicated bus lanes to cut down on traffic delays.

“This route takes no private property, does not go through any residential communities, and connects to the LIRR and subway system in ways that will enable a smooth transfer and reliable transit into Manhattan and elsewhere,” said Port Authority spokeswoman Alana Calmi. “A thorough and independent FAA-led environmental review is underway and will continue to offer multiple forums for public input.”