Time and weather are taking their toll on aircraft displayed at Grumman Memorial Park in Calverton.

On the last Thursday of the month, a handful of former Grumman employees meet for lunch at Watermark of Wading River to catch up, have a few laughs and maybe reminisce a bit about the days when the Calverton aviation testing and assembly plant was at the forefront of developing the nation’s cutting-edge military aircraft and space vehicles.

These men are among the last local remnants of a once-mighty workforce that in the plant’s heyday numbered 4,000 strong. Many are military veterans and retired pilots, engineers and technicians, proud of the tradition of excellence that was forged on the grounds where they built and tested Grumman’s renowned F-14 Tomcat fighter jets from the early 1970s until 2006.

But the former workers are getting on in years and their numbers are dwindling, and efforts to maintain and protect the integrity of the symbol of that excellence — Grumman Memorial Park — get harder every year, they said in interviews last week.

Last month’s $67,000 refurbishing and repainting project on the two planes at the park was largely the result of a campaign by former Grumman employees, some of whom built the park. A similar refurbishing project was undertaken a decade ago, again at the behest former Grumman employees and military veterans, as well as Calverton civic groups.

Since its 2000 unveiling, Grumman Memorial Park has featured a mounted F-14 Tomcat and an A-6 Intruder. The F-14, known for its distinctive variable-sweep wing design, was the U.S. Navy’s main air superiority fighter jet for more than three decades, and played a pivotal role in the Cold War and other conflicts. It’s the plane Tom Cruise flew in “Top Gun,” and a testament to the ingenuity and engineering prowess of the team at Grumman.

The A-6 Intruder was Grumman’s answer to the Navy’s need for an all-weather, long range, low-altitude attack aircraft. Developed in the late 1950s and retired in 1997, squadrons of A-6 Intruders that rolled off the assembly lines in Calverton ran bombing missions during the Vietnam war, Operation Desert Storm and numerous other conflicts around the globe. The plant also developed innovations like the E-2 Hawkeye and the EA-6B Prowler.

Grumman’s Bethpage plant produced the Lunar Module LM-5 “Eagle” for NASA, which landed 12 astronauts on the surface of the moon between 1969 and 1972.

Volunteer groups made up of former Grumman workers and military veterans maintained the park’s aircraft for five years, according to U.S. Air Force veteran and former Grumman plane captain Ken Euring of Mattituck, before turning over that responsibility to Riverhead Town in 2005.

Since then, the former Grumman workers say, the planes’ physical conditions have slowly but significantly deteriorated, despite this fall’s refurbishing and repainting.

The two planes displayed in the tiny park near the intersection of Routes 25 and 25A are on loan from the National Naval Aviation Museum, which has strict maintenance requirements as part of the loan agreement.

The agreement includes mandated annual reports that require detailed descriptions of the physical condition of the planes. The reports must note “all points of concern or deterioration including rusting, fading, scratches, chips, etc.” — as well as current close-up pictures of the aircraft.

During an interview at the park last week, Mr. Euring said that the October repairs “were done extremely poorly,” pointing to some small lights that appear to have been painted over, some decals either peeling, damaged or missing and other indications of general decay. He said that a third of the screws from one panel on the A-6 are missing, allowing rainwater to penetrate the interior, causing corrosion.

“Couldn’t they have put some caulking in it before they painted it?” he asked.

When some of the men that built these planes visit this display, Grumman veterans said, they can’t help but see a lack of the precision they practiced for years when assembling, testing and repairing the fighter jets. Knowing every inch of these planes as they do, they spot damage and defects that an average person might miss.

Mr. Euring was one of the key players in getting the memorial park built. Last week, standing beneath an F-14 mounted on 20-foot concrete pillars, he talked about why the park is so important to him and fellow ex-military and former Grumman employees. He said that when he and his colleagues launched the project in 1998, the property was literally a hole in the ground.

“What are you gonna build on that?” he recalled wondering. “You gave us a 30-foot hole.”

A spectrum of local businesses pitched in with donations of materials and labor. A Calverton trucking company “came in with boulders the size of cars” to fill in the hole, Mr. Euring said. “Suffolk Cement donated all the cement [and] Stony Brook Manufacturing did any welding work for us. We sold [commemorative donor] bricks to raise money.”

He said that during construction, aging former Grumman engineers and technicians came to witness the park’s creation.

“There [were] so many people that came in wheelchairs when we were building this, that came here and cried,” he said.

When construction began, “I would be out there, laying out places where we were going to put [the displays], and people were being brought out by their daughters, their wives — and some of them couldn’t walk, some of the military people. Some had the shakes and whatnot, and [their families] would set them up in chairs and they would just sit there for hours, watching the thing coming together.”

Lee Norberg, a retired Army National Guardsman and Grumman employee now living in South Carolina, said that when well-trained eyes look at the planes in the park, they see what they were trained to see: every crack and flaw and any bit of damage or decay.

“Everything was tolerances in the Navy,” he said, using an engineering term to describe the acceptable range of deviation from a desired measurement that doesn’t cause a product to fail. “Everything was built to tolerances, and they’re tight tolerances. It’s precision. They’ve always got to fit together.”

He acknowledged that the exacting standards he practiced in assembling these planes aren’t necessary for a park display, but he feels it’s disrespectful — to the planes and the people who built them — not to maintain them with more care and attention to detail.

“It’s more of a pride thing,” he said. “At Grumman, the way they put the aircraft together? It was always, always, always top shelf.”

Riverhead’s engineering department manages the maintenance of the park, and assistant town engineer Ken Testa said in an interview that he empathizes with the former Grumman workers. He said that when qualified volunteers maintained the planes it was “great, because they were aviation engineers and manufacturers and technicians and they had the resources.

“Since the town has assumed responsibility we have been doing routine maintenance on the planes under the direction of the National Naval Aviation Museum.”

Still, he said, “we are not really in the business, nor do we have the technical expertise as aircraft maintenance professionals, so we do the best we can.”

He noted that 23 years of exposure to year-round East End weather would give any aircraft a run for its money.

“We’ve gotten some assistance from the Cradle of Aviation Museum in [Garden City]. They’ve been tremendous. They’ve sent volunteers.”

The funding for last month’s project came from grant money, several town officials said, and maintenance and upkeep of the memorial park’s planes has not to date been included in annual budgets. “In the last five to eight years,” Mr. Testa said, “the [planes have] been declining, in the quality of the paint on the planes — where power washing is no longer a solution.”

He said that experts from the company that repainted the planes last month are returning to address the issues that Mr. Norberg, Mr. Euring and others have pointed out in recent weeks.

“We sent extensive photos to the National Naval Aviation Museum, shortly after the job was done, and they were happy,” Mr. Testa said.

He recognizes the reverence for the aircraft, he said, but added that “a lot of this stuff I think the folks from [Grumman] want to see was not really in the scope of the work.”