CHICAGO (AP) — Under orders to trim hundreds of millions of dollars from its budget, the Federal Aviation Administration released a final list Friday of 149 air traffic control facilities that it will close at small airports around the country starting early next month.

Connecticut is losing six: Igor I. Sikorsky Memorial in Bridgeport, Danbury Municipal, Groton-New London, Hartford-Brainard, Tweed-New Haven and Waterbury-Oxford.

The closures will not force the shutdown of any of those airports, but pilots will be left to coordinate takeoffs and landings among themselves over a shared radio frequency with no help from ground controllers under procedures that all pilots are trained to carry out.

Connecticut senators Richard Blumenthal and Chris Murphy said they will fight the closures by offering an amendment tonight in the Senate.

"We are deeply disappointed by the FAA's decision," said a statement from Murphy and Blumenthal's offices. "Closing air traffic control towers at all six of these airports, including one that provides commercial service, will cause needless harm to the residents who work there and the regional economies that depend on their services.

"We will continue to fight to restore federal funding for these towers, which will include offering an amendment tonight that will make it easier to do so. We call on our colleagues in the Senate and the House to join us in this effort to prevent these damaging cuts," Blumenthal and Murphy said.

The plan has raised concerns since a preliminary list of facilities was released a month ago. Those worries include the impact on safety and the potential financial effect on communities that rely on airports as key economic engines for attracting businesses and tourists.

"We will work with the airports and the operators to ensure the procedures are in place to maintain the high level of non-towered airports," FAA Administrator Michael Huerta said in a statement.

The FAA is being forced to trim $637 million for the rest of the fiscal year that ends Sept. 30. The agency said it had no choice but to subject most of its 47,000 employees, including tower controllers, to periodic furloughs and to close air traffic facilities at small airports with lighter traffic. The changes are part of the across-the-board spending cuts known as sequestration, which went into effect March 1.

All of the airports targeted for tower shutdowns have fewer than 150,000 total flight operations per year. Of those, fewer than 10,000 are commercial flights by passenger airlines.

Airport directors, pilots and others in the aviation sector have argued that stripping away an extra layer of safety during the most critical stages of flight will elevate risks and at the very least slow years of progress in making the U.S. aviation network the safest in the world.

Airlines have yet to say whether they will continue offering service to airports that lose tower staff. Any scaling back of passenger service could have major economic impact for communities.

Mark Hanna, director of the Abraham Lincoln Capital Airport in Springfield, Ill., says without ground controllers as backup the risk to operate "goes up exponentially," especially at airports like his, which have such a broad mix of aircraft types: everything from privately operated Piper Cubs to the larger passenger planes of United and American airlines.

That an aviation sector as sensitive as air traffic control could become subject to political brinkmanship in Washington was especially frustrating, he said.

Hoping to escape the final cut, he and other airport directors were left to argue with the FAA about whether the closure of their facilities would adversely affect what the agency described in a letter as the "national interest."