Kendall Jenner and Blake Griffin Catch Dinner and the Movie 'It' in New York

Kendall Jenner and Blake Griffin just took a major step in their dating life -- 'cause nothing says "we're together" like dinner and a movie ... and a 2,475 mile trip.

The rumored couple was spotted grabbing a bite Monday night in NYC at Carbone, and then catching the new horror flick "It" afterward.

Speaking of flying, Blake clearly jetted off to New York to be with Kendall ... who's walking runways for Fashion Week. They'd been seen hanging in L.A. (with pals) prior to this.

If they keep this up ... they'll float too.