GA engines with carburetors normally are of the updraft variety, and as a result can sometimes experience carburetor icing.
Altho of the downdraft variety, many older cars with carbs also experienced icing...the Buick straight and the Chevrolet straight six, are two such examples.
Piston engines with pressure carburetors almost never experience icing...all large radials (CurtisWright turbocompound engines excepted, fuel injection) were thus equipped.
I've personally flown many...no carb icing problems that I can recall.
Regarding leaning at altitude with cars equipped with carburetors, years ago such cars sold in Denver (for example, elevation 5280 feet) were especially equipped with smaller jets, and were especially designed for such heights.
As a result, they ran quite lean lower down...poor results were obtained, unless you changed the jets.