American Eagle Flight 5342 carrying 64 passengers from Wichita, Kansas, struck a military UH-60 over Washington, D.C., Wednesday night. Fuselage from the two aircraft plunged into the Potomac River. There are no survivors expected on either vessel, according to the Washington, D.C. fire chief, making Wednesday’s devastation the deadliest U.S. airplane crash since February 2009, when a Colgan plane crashed outside Buffalo, New York, killing 50.

The Federation Aviation Administration, National Transportation Safety Board, and Pentagon will investigate the disaster.

The flight’s Reagan airport destination, also known as DCA, is the country’s busiest runway and a hub for incoming government officials, dignitaries, and legislators. Originally built to accommodate 15 million passengers annually, Reagan sees 25 million travelers every year. 

“It’s a beehive of activity,” Dennis Tajer, an American Airlines captain and spokesperson for the U.S. pilot union Allied Pilots Association, told the Washington Post. “It’s extremely compact, and it’s a high volume of traffic.”

The high volume of travellers at the airport is correlated with several close safety calls. In 2024 alone, DCA saw at least eight near-miss incidents, according to the FAA. In May, an American Airlines flight headed to Boston had an almost-collision with another aircraft after speeding down the runway at about 100 miles per hour before being ordered to stop. The Metropolitan Washington Airports Authority, which operates Reagan, directed Fortune to the FAA for comment, and the FAA did not immediately respond to Fortune’s request.

Some safety experts say the near-misses at DCA are a reflection of a broader trend of almost-collisions happening in commercial aviation. The FAA reported 1,757 almost-collisions total in fiscal 2024, about the same as the 1,760 reported the year before.

“The past two to three years, we’ve had several close calls at various airports in the U.S.—between the airplanes on the ground having issues and almost colliding on the runway and taxiway,” Anthony Brickhouse, a U.S.-based aviation safety expert, told Fortune. 

“In safety, what we look for is trends…and when trends happen over and over again, if changes aren’t made, that near-miss becomes a mid-air collision,” he added. “And unfortunately, that’s what we had last night.”

The political battle over DCA

Regulating traffic at DCA has been a hotly contested issue. Ronald Reagan, along with New York’s LaGuardia Airport, are uniquely subject to a decades-old perimeter rule, which limits travel to within 1,250 miles to or from the respective airports. While proponents of the rule argue changes to it would cause more congestion and stress airport systems, others have pushed back against the law, arguing less restriction could help create new jobs and help meet high flight demands. 

Rep. Blake D. Moore, a Republican representing Utah, has advocated tweaking the law enforcing the perimeter. Moore told the New York Times in July 2023 the loosening of the rules would encourage tourism between D.C. and his Salt Lake City hometown. He also said it would make a more convenient commute for him—a perk other legislators, both Democrat and Republican, would share. Moore did not immediately respond to Fortune’s request for comment.

Those wanting to slacken the perimeter rule notched a victory in October, when the Transportation Department, under pressure from some airlines, awarded five new long-haul routes from Ronald Reagan to major airlines, including Delta, United, and American Airlines.

Last May, when Congress was considering an FAA reauthorization bill that would grant DCA those flight slots, Democratic Sen. Tim Kaine, who represents Virginia, opposed the bill and told reporters more routes at the hub could cause a collision.

“God forbid waking up and looking in a mirror one day and say, ‘Wow, I was warned,” Kaine said. “I was warned, and I shouldn’t have done this.”

A multi-pronged problem

Aviation safety expert Brickhouse warned against placing blame for the crash on Reagan airport. He said there’s still not enough information as to why the crash happened and that, in instances of safety, numerous factors contribute to safety outcomes.

Beyond airport congestion, safety bodies like the FAA and NTSB will probe pilots and their experience, air traffic control, and any technology malfunctions, he said.

Historically, myriad issues have contributed to near-misses. In fiscal 2023, about 60% of total runway incursions were a result of pilot deviations, about 20% were due to air traffic controller action or inaction, and the other 20% were due to pedestrian or vehicle deviations, NBC Washington reported last April after a near-miss at DCA, using data from the U.S. Department of Transportation.

Earlier this month, President Donald Trump announced he would fire the heads of the Transportation Security Administration and Coast Guard and gut the aviation safety group Aviation Security Advisory Committee formed in 1988. The group—composed of airlines, unions, and other key players to recommend changes to the industry—will continue to exist, but won’t have any personnel.

Identifying which issues were key contributors to Wednesday’s tragedy will take patience, Brickhouse said.

“Safety is something that you always work towards, because different threats, different hazards and different risks are always presenting themselves,” Brickhouse said. “As safety professionals, our job is to constantly be aware of those changes that happen so that we can make the proper adjustments to maintain a high level of safety.”