I don't think one can begin the know the full story of "helicopters on Wilshire Boulevard" without finding out why Democrats planned to take one of Pelosi's lavish, taxpayer-paid overseas trip mid-January during the December 2018-January 2019 (35-day) government shutdown that would have likely kept them outside the US for what became the helicopter incident. Adam Schiff, Chuck Schumer, and literally all of Nanzi Pelosi's family "coincidentally" would have been out of the country for the possible disaster of what seems to have been squelched at Wilshire Boulevard.
It was the time of government shutdown when Pelosi's large entourage headed out 1/17/2019 in Air Force buses to fly off to Belgium, Egypt and Afghanistan. She inexplicably said she wanted to do that to "show appreciation and thanks to our men and women in uniform" and "obtain critical national security and intelligence briefings from those on the front lines," as if those could not have happened via secure A/V lines. It is not known that such unique briefings and/or appreciation events ever took place.
Yes, that's what Ms-Two-Heartbeats-Away-from-the-Presidency does during a government shutdown while surrounded by literally her entire family. "Tut-tut," PDJT implicitly said as he disallowed her family's and her delegation's jet travel at government expense, turning the buses around, even as their occupants sat for hours, still hoping to find a resolution that would allow them to make the trip. PDJT made clear the group could have gone commercial--or charter, for example--but the Dems chose not to do that. The entourage would have been out of the country when the miltary helicopters flew in downtown LA.
You'll perhaps also recall that shortly before that incident Pelosi talked about canceling the State of the Union Address and her becoming president as if both of those might well come to pass.
On the evening of 2/5/19, the military helicopters stopped and ten troops exited a building near the corner of Wilshire and Lucas, owned by Thomas Girardi, the lawyer for the NXIVM sex cult, and embarked the helicoptesr with two apparently-heavy loads carried by three persons each. Subterranean access in that very area linked both the LA underground rail system and the Standard Hotel.the LA underground rail system and the Standard Hotel.