I was surprised too....
One another board I follow, which shall remain nameless, there was some interesting, if unconfirmed, information about the choppers origin....
I've been quietly following the wild west as well (reddit aviation). That rumor, based on where the helicopter's tracking started, in the fancy western suburbs around McLean, was countered by an assertion that tracking doesn't always start where the plane starts. Reports now are that is was flying to and from Fort Belvoir, near Mount Vernon, south of the airport. Military planes can have the transponder off, and in the tower are tracked from the ground by triangulation, it's said. What is confirmed is that the helicopter was supposed to be under 200 feet and along the east bank of the Potomac at the crash site, instead of about 375 feet and in the middle of the river. The other issue is one controller in the tower instead of two. My prediction is that due to the labor shortage, the FAA will not broadly fire/resign controllers, as has been more or less threatened politically, but may add new ones on a less inclusive basis, maybe using contractors or the military. The NTSB may get drawn into politics as well, which would be a first.
Broadly, the military is a different world, highly respected in my parts, but well-known enough to garner some realism, inside and out. It has its own labor challenges, and has a rules-based diversity that even extends to non-citizen recruits, such as from Mexico and the Philippines, US territory for the whole first half of the 20th century. Naval areas like San Francisco and Norfolk have higher Filipino populations than some cities in the Philippines. (Just an example of diversity, not related to the helicopter.) The rules have worked out to be a strength. They can be jarring to outsiders. As an example, a captain asleep in the bunk when a ship crashes loses his or her command, and career (officers have to advance). It was big news when that practice was not followed in an incident in the western Pacific a few years ago. Another example of order is that the top admiral in North American NATO is always French. (The de Gaulle rift is over.) That may explain why French shipping giant CMA CGM has its US HQ in Norfolk.
DCA used to be restricted to flights serving St. Louis and east. Once that restriction was lifted, it's been continuously growing, and mandated by Congress to allow more flights. It is now somehow a hub for American Airlines. With the general increase in flying, it's not clear IAD and BWI could handle the percentage they used to. BWI would certainly give it a go. Back in my day EWR in New Jersey was tumbleweeds and now it's highly congested. DCA is ultra convenient to Washington, and even LGA in New York is fairly so. I took a fast water taxi to Wall Street from there once, from the pretty former Pan Am terminal, the old Marine Air Terminal. Miami has a similar Art Deco former seaplane terminal, now the surprisingly compact City Hall.
It strikes me the new Silver Line Metro to IAD is somewhat like the 1970s Train to the Plane on the NYC subway, the lux version of the A Train. It also takes an hour, and a taxi is also usually faster, but not only train nerds find the Metro more relaxing and predictable. The latter didn't really apply to the Train to the Plane, despite the marketing. The Silver Line is successful, despite the lamentable compromises building it.
One suggestion I've read is for military training around DCA to take place after 10 PM, when commercial flights end, and the reason there was one controller rather than two at 8:30 PM. (They're overworked and the supervisor let one go home.)
For those of us who remember the 14th Street Bridge crash in 1982, also into an icy Potomac, it's now even more heroic to remember two bystanders named Roger Olian and Lenny Skutnik jumping into the water to save people. Reminiscent of Sullenberger on the Hudson. Sadly it's not often possible. And that taxi trip to IAD is more dangerous than flying.