... I should've probably done this when I got in with Ikki, but I've never had to use it, and well. I kind of want to now, what with things happening in camp and the fact that I can ABUSE something for crack purposes. So, suffice to say, there are some spoiler-ish stuff under these cuts!
Okay, so! Ikki is the Storm King of the Hurricane Road - formerly the Wind King of the Wing Road, but because that was "too constricting" he got the new name from the old man.
Ikki's abilities, aside from fighting with his fists and being able to use his A-T, is that he's able to manipulate the air's surface; when he was hospitalized, Sora taught him how to do this, in order to prepare Ikki's body for using the Regalia.
Have some quotes, because quotes are love and... lol Oh! Great:
"Then I ask you... what do you define as the beginning of the sky? At one hundred meters or even one thousand meters, it isn't much different from right here - the sole difference is the air density and matter concentration. So... This is where the sky begins. Anything above the Earth belongs to the domain of the sky.
Air diffuses easily, even if only minor differences in air pressure appear, the density of the air still changes. The air moves to fill in that gap in pressure. That is the wind. In short, the "wind" is the result of changing destiny, which in turn, causes a relative shifting in velocity in the atmosphere.
Many things precede the wind. Sound appears first. The inner may detect the pressure change. The moving wall of air creates pressure which in turn is followed by a change in humidity.
The density of the wind is much higher than stagnant air. Theoretically, it is even possible to aerodynamically ride that pressure gradient like a plane and obtain shift. With the addition of the upward force of lift, the distance of any jump naturally increases." Yoshitsune; Chapter 102
This was explained while Ikki's was doing the Devil's 33, and it was being pointed out that his jump was getting higher and further.
Later on, during Sora's training with Ikki, this comes into play again, but as the air being a surface, instead of a way to increase a jump distance or whatever.
"The space between my palm and the floor is one surface. Also, the space extending from the backs of my hands to the limits of the atmosphere forms the surface. Acknowledge the division and control it." Sora; Chapter 120
"The most important thing is... surface! The division between air of different densities... the division two winds..." Ikki; Chapter 129
... 8D Y-Yeah, but I have awesome castmates, and they basically summed it up as such: "He can touch the air like it's a solid surface, and thus push it, creating wind."
Now onto the Wing Road!
The Wing Road, as described by Wiki, is as such: "Uses interfaces to create and ride on the surface of different air densities." Which is part of what I said earlier! So Ikki can not only ride these different interfaces, as the Wind King, he can manipulate them and even use them to attack.
With the Regalia: "Can create countless trick paths throughout the air, and produce gusts of wind strong enough to even nullify some of the other Regalia's Infinity Atmosphere. Through activating the Regalia's core, powerful windstorms with wind speeds over 180mph can be produced, and controlled by the user."
Now, Ikki doesn't have the Regalia that go with his Road; he had an inferior version in his fight with Ringo, but they broke after only being used twice, and Sora has the version Kururu made, so that entire last paragraph will most likely not come into play. However, Ikki can still ride and use the Wing Road! Which... will also not come into play a lot, but this is mostly for my own reference, so.
Also, as I said above, Ikki's new title is the Storm King of the Hurricane Road - which is the same, but yeah. Again for my own reference. There hasn't been anything new to add to it, but if canon ever comes out with more, well.
Wiki reference:
Air Gear: Kings and Roads