Since it opened in 2003, Café Saint-Ex has rightfully earned its wings as a go-to neighborhood spot. The restaurant was a pioneer when it landed on 14th Street, just below U Street, bringing folks to an area that didn’t look like much then, but now bustles with shops and restaurants. Perhaps the secret to the success of the aviation themed Saint-Ex — named for “The Little Prince” author Antoine de Saint-Exupery, and themed for his career as a World War II pilot — is the European-style patio that nearly always teems with happy customers. Or maybe it’s the Art Deco bar and the actual World War I biplane propeller mounted behind it. It could also be that the restaurant’s downstairs bar, Gate 54, is the place to go for a post-Black Cat drink. But it’s the cooking of Chef Billy Klein that keeps them eagerly returning. Adept with classics like burgers and BLTs, Klein also shows his prowess with more nuanced dishes, like luscious sunchoke soup with a crispy nugget of goat cheese; udon noodles in a broth rich with pork belly, pea shoots and a poached egg; and velvety ice creams like bananas Foster and cranberry.  We’ve already booked a return flight.