Well, all this talk 'bout skybaxes and nothin' on the critters themselves. Time to rectify thet, here an' now. Keep in mind thet a skybax, like any flyin' critter, can only fly if it is carrying a light load or less. Any heavier'n that, an' they're forced to walk jes' like the rest of us.
In-game stat blocks are found at the bottom of the page ~ XB

Skybax, Broadwing
Large animal
Hit Dice: 4d8+12 (30 hp)
Initiative: +6 (Dex)
Speed: 30 ft., fly 200 ft. (poor)
AC: 17 (-1 size, +6 Dex, +2 natural)
Attacks: Beak spear +5 melee
Damage: Beak spear 1d8+4
Space/Reach: 10 ft./10 ft.
Special Attacks: --
Special Qualities: Low-light vision, superior vision
Saves: Fort +7, Ref +10, Will +6
Abilities: Str 17, Dex 22, Con 17, Int 2, Wis 14, Cha 6
Skills: Listen +7, Spot +11*, Survival +7
Feats: Endurance [B], Flyby Attack [B]

Climate/Terrain: Temperate, subarctic and subtropical coast
Organization: Pair or flight (5-20)
Challenge Rating: 2
Treasure: None
Alignment: Always neutral
Advancement: 5-12 HD (Huge), 13-25 HD (Gargantuan)

On the ground, skybaxes resemble bizarre giraffes crossed with baboons, folding their wings up into their "armpits" and able to use their three-fingered hands at the wings' wrist joints to hold things. They can walk bipedally or quadrupedally, though when walking on two legs, their knees bend like a human's, which is sometimes difficult to get used to. They are also able to sit squarely on their haunches like an ape.

Broadwing skybaxes, also known as crested skybaxes, are generally found in the cooler regions of the world. As their names suggest, they typically have short, broad wings and any of an assortment of head crests, from simple spikes to huge sail-like structures. Most domesticated broadwings are flown with an undersling harness, to keep the rider from being repeatedly bashed by the crest.

Their temperament is gentle and a little skittish. Despite their huge wingspans (from 18-40 feet), their compact bodies and large heads are fragile in a confrontation, and their wings are especially easy targets.

Combat
If confronted, a skybax's first reaction is to fly away. If this fails, or if a nesting ground is threatened, a skybax typically uses its flyby attack in an effort to spear an enemy with the least risk to itself. If caught on the ground, though, a skybax is surprisingly nimble and tries to face the opponent that poses the biggest threat, lancing with its great reach.

Low-light vision: A skybax can see twice as far as a human in conditions of poor illumination.
Superior vision: A skybax can see five times as far as a human in good lighting conditions.

Training a skybax
Training a skybax as an aerial mount requires a successful Handle Animal check (DC 24 for a young creature, or DC 29 for an adult) and that the skybax be domesticated (hatched in captivity and raised around people).

Broadwing eggs are worth 100 gp each on the open market, while domestic chicks are worth 500 gp each. Professional trainers charge 250 gp to rear or train a skybax, and riding one requires a skybax harness. A skybax can fight while carrying a rider, but the rider cannot also attack unless he makes a successful Ride check.

Carrying capacity
A light load for a broadwing skybax is up to 150 pounds, a medium load is 151-200 pounds, and a heavy load is 201-250 pounds.

On the ground, skybaxes resemble bizarre giraffes crossed with baboons, folding their wings up into their "armpits" and able to use their three-fingered hands at the wings' wrist joints to hold things. They can walk bipedally or quadrupedally, though when walking on two legs, their knees bend like a human's, which is sometimes difficult to get used to. They are also able to sit squarely on their haunches like an ape.

Longwing skybaxes are usually crestless, or have minimal crests, aerodynamically compensating by having a much longer head than broadwings. They are generally found in warmer climes, and tend to have much more vibrant colors in their coats. Their wings are narrow and long, the front wing's "pinky" being typically over twice the length of the arm. Domesticated longwings are usually ridden with a back harness, which seems to help the skybax balance the rider.

Their temperament is gentle and a little skittish. Despite their huge wingspans (from 30-60 feet), their compact bodies and enormous heads are fragile in a confrontation, and their wings are especially easy targets.

Combat
If confronted, a skybax's first reaction is to fly away. If this fails, or if a nesting ground is threatened, a skybax typically uses its flyby attack in an effort to spear an enemy with the least risk to itself. If caught on the ground, though, a skybax is surprisingly nimble and tries to face the opponent that poses the biggest threat, lancing with its great reach.

Low-light vision: A skybax can see twice as far as a human in conditions of poor illumination.
Superior vision: A skybax can see five times as far as a human in good lighting conditions.

Training a skybax
Training a skybax as an aerial mount requires a successful Handle Animal check (DC 24 for a young creature, or DC 29 for an adult) and that the skybax be domesticated (hatched in captivity and raised around people).

Longwing eggs are worth 200 gp each on the open market, while domestic chicks are worth 800 gp each. Professional trainers charge 400 gp to rear or train a skybax, and riding one requires a skybax harness. A skybax can fight while carrying a rider, but the rider cannot also attack unless she makes a successful Ride check.

Carrying capacity
A light load for a longwing skybax is up to 175 pounds, a medium load is 176-250 pounds, and a heavy load is 251-300 pounds.