WATCH LIVE:

Big B-2 flyover with both leaders on the tarmac, just after the handshake...

Update(1430ET): President Trump said just before landing in Anchorage that "there's a good respect level on both sides" - but he has also threatened to "walk" if things don't go well.

Trump told Fox News' White House correspondent aboard Air Force One that if his meeting with Russian President Vladimir Putin doesn't go well, "I would walk." According to the brief exchange:

"I mean, if it doesn't, you walk?" Baier asked.

"I would walk, yeah," Trump said.

But Trump also struck a tone of optimism: "I think we're going to do very well. Our country is doing very well. We're setting records economically like we never have before, including the stock markets are all at record high," he said.