Point of View
The story in Capra's film unfolds in a pretty linear way, though at first we have some catching up to do—which is why there's so much exposition given upfront during the first scene, on the private cruise ship.
There are twists and turns once Ellie and Peter meet, to be sure; obstacles and ordeals abound in It Happened One Night. But on the other hand, it's clear to the audience once the two travelers meet that it's only a matter of time before they'll fall for each other and, eventually, end up together.
So the film combines suspense (we're kept on the edges of our seats wondering if they'll end up together) with certainty (we're sure all along, deep down, that they'll end up together, this being a Hollywood rom-com and all). At the same time, Capra combines narrative complications (all the twists and turns, obstacles, and ordeals) with a straight-ahead, "cruise-control"-type story that only needs to be set in motion in order to head straight for its resolution.
These may seem like incompatible halves, but seeing It Happened One Night should be enough to convince you that they really do form a whole. And it's by bringing them together that Capra works his narrative magic, casting his cinematic spell over us.