Update(1340ET): Zelensky has arrived on a large Air Force jet. He's expected to soon meet Biden at the White House, after which there will be a joint presser at 1630ET.

Update(10:45ET): Zelensky is reportedly arriving to Washington D.C. aboard a US Air Force plane, according to US officials cited in CNN, after taking a high risk train ride into Poland. White House national security communications coordinator John Kirby said of the impending visit with President Biden, "The President really believes that as we approach winter, as we enter … a new phase in this war, of Mr. Putin's aggression, that this is a good time for the two leaders to sit down face to face and talk." But this is how Reuters somewhat cynically previewed the visit: 

Ukrainian President Volodymyr Zelenskiy headed to Washington on Wednesday to meet President Joe Biden, address Congress and seek "weapons, weapons and more weapons" in his first overseas trip since Russia invaded Ukraine 300 days ago.