Let's see what he came up with (click images to enlarge):
Gallery
Above are images of Loewy's 1932 Hupmobile design. The most distinctive feature being front fenders that fairly tightly wrapped around the tires. Some observers retrospectively call these "cycle-fender Hupps," but the term is relative: true cycle-type automobile fenders lack the curved transition to the running board and wrap the tires even more fully. Otherwise, the Loewy design was a cleaned-up version of normal 1930 vintage style.
Loewy's 1934 design was fairly radical for its time. The most conspicuous features aside from the rounded-off shape are the three-piece "wraparound" windshield (a similar windshield design was on the 1934 Panhard) and the headlights blended into the hood. The upper photo seems to include professional models and the lower features El Brendel, a comic popular at the time.
This advertisement shows the rear of the car (though the back windows are depicted smaller than they really are). The ad includes a pitch for Hupp's aerodynamic design by noted aeronautics professor Alexander Klemin.
Sales of 1934 Hupps were disappointing, so the facelift for 1935 models included a reversion to a conventional one-piece windshield and a redesigned grille and front bumper. I suspect that Loewy was not involved with this facelift, so invite Hupmobile mavens to set the story straight in Comments if I'm wrong.