Lieutenant Tom "Iceman" Kazansky's name says it all: he's an iceman, plain and simple.
What does that mean? Well, for starters, it means he's one cold told. The only time he seems to smile is when he's giving Maverick a hard time. And even when he does smile, it's really more of an arrogant sneer of sorts, the "I know I'm the man" kind of smile.
Even though he's kind of cold, though, he's a textbook pilot, and pretty much the best there is. As Goose says to Maverick at the nightclub:
GOOSE: That's the way he flies, ice cold, no mistakes.
Toss into the mix the fact that Iceman is a decently tall guy, has good hair, a great tan, and a great body, and it becomes clear that he's the guy who could have been a model. Sure Maverick is a good-looking dude, but he's not quite tall enough to be a model.
A One-Note Role
Iceman doesn't develop too much throughout the movie. He never really makes any big mistakes during training, and he doesn't really seem to need to learn any big emotional lessons like Maverick does. In a lot of ways, there's not a lot of depth to Iceman. He's in the film to be Maverick's antithesis and antagonist-turned-buddy, and he's the perfect fit: he's blond, Maverick is dark-haired; he's taller, Maverick is slightly shorter; he's number 1, Maverick is number 2.
If there's one thing Top Gun wants us to take away about Iceman, it's this: sometimes it may seem like you have everything, but sometimes everything isn't enough. Iceman is the man, there's no question, but he doesn't have the same instincts as Maverick.
It's Maverick that ultimately saves the day. It's Maverick that Viper takes a special interest in, and even volunteers to fly with, should the need arise. If Iceman looks great on paper, he lacks the intangibles. That's what Maverick has, and Iceman finally realizes that by the end of the film. He knows Maverick saved his butt, and that is why he tells Maverick that, even though he's still dangerous, he can be his (Iceman's) wingman anytime.