Representative Blake D. Moore, Republican of Utah, is pushing for changes to federal law that would allow more nonstop flights between Ronald Reagan Washington National Airport and Salt Lake City. Those flights, he said, would increase tourism between Utah and the nation’s capital.

They would also offer Mr. Moore a more efficient commute.

When he heads home from Capitol Hill, Mr. Moore often waits for the only direct flight in the afternoon or evening from any of the three Washington-area airports that can return him to Salt Lake City in time to tuck in his children: a Delta Air Lines departure from Reagan National, also known as DCA, after 5 p.m. that lands around 8 p.m. An earlier departure would allow him to fulfill his duties as a legislator but also as a father, Mr. Moore said, letting him help his wife with dinner or attend Little League practice.

“We need more direct flights out of DCA,” he said.

In recent weeks, dozens of lawmakers have joined the push for 28 new round-trip flights per day at Reagan National. Pressing their case with opinion essays, tweets and proposed legislation, they argue that these additional routes — which would require tweaking a decades-old law that prevents most flights from traveling more than 1,250 miles to or from Reagan National — would meet pent-up demand, reduce airfares and create new jobs.

Their push, fueled by a multimillion-dollar lobbying campaign sponsored by Delta, aims to enact changes as part of legislation that would reauthorize the Federal Aviation Administration for another five years.

The effort to relax the so-called perimeter rule is caught up in battles for market share among airlines, local politics in the Washington area and friction over the F.A.A.’s chronic and worsening problems managing air traffic and safety.

But unlike many of the special-interest battles in Washington, this one has personal ramifications for lawmakers — or at least those who shuttle home each week to points west that cannot be reached easily from Reagan National, located just across the Potomac River from downtown Washington and a quick ride from Capitol Hill. (Another Washington-area airport, Washington Dulles International Airport, is about 25 miles to the west.)

“I absolutely would be in favor” of additional direct flights from Reagan National to points outside the current 1,250-mile perimeter, said Senator Jon Tester, Democrat of Montana, adding that he would need to see more details before supporting any particular bill.

Mr. Tester described his commute — which involves a pre-dawn, 90-minute drive from his farm near Big Sandy, Mont., to Great Falls International Airport and a layover in Minneapolis, Salt Lake City or Denver — as “a pain.”

Representative Burgess Owens, Republican of Utah and one of the lawmakers seeking to allow more long-distance flights from Reagan National, said he had recently missed one from Salt Lake City to Washington and had to wait a day and a half for another.

Ultimately, he had to fly into Baltimore/Washington International Thurgood Marshall Airport, roughly 25 miles northeast of Capitol Hill, and take an hourlong Uber ride to his office. “Unfortunately, many Utahns and Americans from the West lack access to their representatives, our nation’s historic sites and federal agencies,” he said at an event outside the Capitol promoting legislation to authorize additional flights.

It is not clear whether public policy will be swayed in this case by questions of whether members of Congress should be able to avoid inconvenient connecting flights or have more options at a nearby airport. And other issues are at play.

Lawmakers from Maryland and Virginia, the states that would be most affected by increased flights in and out of Reagan National, have argued that the airport, in Arlington, Va. — a spot that an energetic traveler could reach on foot from the Lincoln Memorial — is already strained by traffic, limited parking and stressed baggage systems.

“Right now, DCA already has the busiest runway in the country,” Representative Abigail Spanberger, a Virginia Democrat who opposes the proposed perimeter exceptions, said in a statement. “I’m also concerned in the wake of a recent F.A.A. analysis that found that more long-haul flights at DCA would throw the airport’s operational performance out of balance.”

United Airlines and American Airlines, Delta’s biggest competitors, are also opposed to relaxing the perimeter rule. Those carriers argue that additional long-distance flights at Reagan National would cause passenger delays and might even waylay the F.A.A.’s reauthorization. And if the perimeter changes were passed, yet another industry tussle over which new routes could ultimately be offered would likely follow.

In an internal memo in May, the F.A.A. wrote that adding long-distance flights to Reagan National’s schedule without taking away existing ones would strain the system. Reagan National already ranks as No. 10 among U.S. airports in delays, the memo said.

But supporters of the shift consider their own unwieldy commutes to be evidence of a system in need of improvement.

In April, Delta established a nonprofit called the Capital Access Alliance to make the case for adding new exceptions to the perimeter rule, which dates to 1966 and has been updated occasionally over the years.

Joined by small businesses; West Coast companies like Columbia Sportswear and Adidas; and trade associations in states like Utah, Texas and Washington, the alliance says the perimeter rule has outlived its usefulness as a bulwark against airport congestion and competition that could have hurt Dulles — which opened in 1962 — in its early years.

The group also says that the congestion issues that the F.A.A. has flagged are not a factor during certain times of day, creating an opening for new flights.

Delta is also hoping to operate lucrative new long-distance flights to and from Reagan National, where its current market share is 14 percent, according to a Boston Consulting Group analysis commissioned by the airline. Delta officials say they hope to establish or increase service to cities including Austin, Texas; Salt Lake City; and Seattle.

Delta has hired the influential lobbyist Jeff Miller, who is known for having Speaker Kevin McCarthy’s ear, to help its case.

Jamie Baker, an airline analyst at JPMorgan Chase & Company, said that while it was too early to predict the financial implications of exceptions to the perimeter rule for major airlines like Delta, the changes could result in reduced service to smaller cities from Reagan National.

Defenders of the perimeter rule have emphasized that possibility.

“Cities and states that rely on convenient, on-time access to Washington as a destination or connection risk losing access,” a nonprofit called the Coalition to Protect America’s Regional Airports says on its website. The group is backed by United and dozens of smaller airports and trade groups, many of them within the current 1,250-mile perimeter.

But the lengthy journeys that lawmakers can face en route to Washington appear to have inspired some to push for new exceptions to the existing limits.

In May, Representative Hank Johnson, a Democrat from Delta’s home state of Georgia, and Mr. Owens, the Utah Republican, introduced legislation that would allow 28 new daily round-trip flights at Reagan National. Senators Raphael Warnock, also a Georgia Democrat, and Cynthia Lummis, Republican of Wyoming, introduced a similar bill in the Senate in June.

“The operations of DCA remain as they were structured in the 1960s so as to protect the ability of Dulles International Airport to grow,” Mr. Johnson said. “Those ideals have outlived their usefulness at this point.”

Among those seeking to relax the perimeter rule is Representative Chip Roy, Republican of Texas, who wants to see direct flights between Reagan National and San Antonio, parts of which are in his congressional district.

Mr. Roy can take a direct flight from Austin to Reagan National, he said, but sometimes that flight does not arrive early enough for him to make meetings of the House Rules Committee, forcing him to use Dulles or Baltimore/Washington instead.

“It’s a little bit clunky,” Mr. Roy said.

Senator John McCain, Republican of Arizona, tried to relax Reagan National’s perimeter restrictions in the late 1990s and to get rid of the rule entirely in the late 2000s. While Mr. McCain was not able to eliminate the rule, he did succeed in winning new exceptions to create flights from Reagan National to Phoenix in the process. He continued to take flights home with connections, however, to avoid accusations of self-dealing.

The impact of the push by Mr. McCain, who died in 2018, was such that Representative Debbie Lesko, a Republican from the Phoenix area, is declining to support the effort by some of her House colleagues to loosen the perimeter rule, fearing that it could backfire on Arizona.

“We do have several direct flights to Phoenix already,” Ms. Lesko, who flies direct to Reagan National, said with a chuckle, “and so opening it up to, let’s say, Utah or things, may reduce the number of direct flights to Phoenix. So for my constituents, I don’t think I would sign onto that bill.”

Kitty Bennett contributed research.

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