Looks like an oversight. The PRD entry also lists air subtype, but no fly speed and maneuverability.
Although I'm surprised an Ice Elemental has the air subtype at all; doesn't make sense to me. *shrugs*
Ruyan.
Ice doesn't fly. The Air subtype is for what they resist or are vulnerable to.
Penguins have wings and are considered avians but they don't fly either.
Being a naturally occurring creature, and being a creature made of primal, magical, elemental forces, are two ENTIRELY separate matters. It specifically states that all creatures with the (air) subtype can fly. If the Ice Elemental is an exception to this, that's fine - but a reason for that exception should be pointed out.
The actual quote is as follows - "Air creatures always have fly speeds and usually have perfect maneuverabiltiy."
-Bestiary I, pg. 310
-Bestiary II, pg. 306
-Bestiary III, 303
There's a handful of places where subtypes that are supposed to "always" have a property don't. There's some anemones and clams and stuff that are aquatic but which have no swim speed. 3PP are significantly less careful about this sort of thing, but there's a handful of core examples.
You may also want to look in those books and see that the Ice elemental is native to the (Water) plane where it meats the plane of Air, not the other way around.
On top of this if you look, out of the 8 elementals, those that have a fly speed don't have any other form of movement besides fly.
Just saying.