Emirates' first Athens to Newark, N.J., flight will arrive in Newark Sunday night, a sign that so far the U.S. government has done nothing to limit the ability of the subsidized Middle East carriers to menace the U.S. airline industry.

Newark is a hub for United (UAL) - Get Report . United also flies between Newark-Athens, but only in the summer. The route has not had year-round daily service since 2012.

American (AAL) - Get Report , Delta (DAL) - Get Report and United have battled incursions by the big three Middle East carriers - Emirates, Etihad and Qatar -- for two years, but they are stepping it up for the Athens-Newark flight, which is particularly unsettling because it is a fifth freedom flight.

In aviation law, fifth freedom flights operate between two foreign countries. Despite their rapid buildup on U.S. routes, the Middle East three operate only one other fifth freedom flight to the U.S. ---Emirates' Milan to New York's John F. Kennedy International Airport. 

On Wednesday, 25 members of Congress from New York and New Jersey wrote to President Trump, urging him to limit the Middle East carriers' U.S. operations.

On Sunday, United employees, labor leaders and Congressmen Josh Gottheimer and Donald Payne, both New Jersey Democrats who signed the letter, will stage a demonstration at the airport.

"We want to express our displeasure with the continued expansion by these massive subsidized government entities, in direct competition with our employers, and with the adverse effect it will have on our employers and our jobs," said Tim Canoll, president of the Air Line Pilots Association, which represents United pilots.

"It's working for {the Middle East carriers}," Canoll said. "They're buying market share with subsidies, and they are not restrained by the price of fuel or the demand for seats. Because they are subsidized, they operate outside the market.

"They take deliveries of widebody aircraft every month," he said. "They have to fly them someplace."

In their letter, the members of Congress urged Trump to prohibit the Athens-Newark flight. (This seems unlikely.) They also asked that he enforce Open Skies agreements.

The agreements were intended to promote competition, absent subsidies, but they have turned into lopsided deals where the Middle East airlines fly nearly two dozen daily flights to the U.S., while U.S. airlines do not fly a single flight to Dubai, Doha or Abu Dhabi.

"We're hoping the president will take this issue up," Canoll said. "It meets his objective to enforce our trade agreement and do what's right for American workers."

The CEOs of American and Delta have said their main interest is to prevent the fifth freedom flights.

Like Emirates, American, Delta and United all fly between New York or Newark and Milan. But since the Emirates flight began in 2013, the U.S. carriers have lost 20% of their market share, according to an economist's report prepared for the Partnership for Open and Fair Skies, which represents the three U.S. carriers and most of their labor unions.

"Local fares between EWR/NYC and Milan have been driven to the lowest of any major European city from Newark/New York," the report said. "The fact that Emirates' local EWR/NYC filed fares to Athens are even lower than those to Milan suggests that Emirates' motive for entering this route is not to earn a profit, but rather, is provocative, predatory, and meant to drive the U.S. carriers permanently out of this market."

In a prepared statement, Emirates President Tim Clark said, "The Greek Government and Athens International Airport approached Emirates some time ago to consider serving the route between Athens and New York. After careful review, Emirates concluded that extending one of our Dubai-Athens flights to Newark would be commercially and operationally feasible.

"We are pleased to be able to help meet a strong consumer need long neglected by other airlines," Clark said. "The availability of high quality, daily international air services is essential for the development of business and cultural ties."

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.