Winged Mount
Your mount acquires a template giving it wings and special abilities.
Prerequisites: Bonded mount or animal companion class ability (an animal companion must be trained to serve as a mount), effective class level 11th.
Benefit: The bonded mount or animal companion acquires the half-celestial (for good characters), half-fiend (for evil characters) or half-dragon template. If you have more than one animal companion or bonded mount, choose one to receive this benefit. If you lose or dismiss an animal companion or bonded mount, you may apply this feat to the replacement creature.
Special: You may select this feat more than once. The effects do not stack. Each time you take the feat, it applies to a different animal companion or bonded mount. If a paladin selects this feat, his bonded mount loses the celestial template for the new one. An animal companion or bonded mount can't benefit from both this feat and the Boon Companion feat.
Notes: I believe that this feat is more or less equivalent in power to Boon Companion, which gives 4 levels up. But if this feels too powerful, maybe this other feat could to for characters longing for winged mounts.
Airborne Mount
Prerequisites: Bonded mount or animal companion class ability (an animal companion must be trained to serve as a mount), effective class level 5th.
Benefit: The bonded mount or animal companion acquires the airborne simple template (from The Genius Guide to Air Magic). It can grow batlike, dragonlike or birdlike wings, suiting the character's desire. If you have more than one animal companion or bonded mount, choose one to receive this benefit. If you lose or dismiss an animal companion or bonded mount, you may apply this feat to the replacement creature.
Special: You may select this feat more than once. The effects do not stack. Each time you take the feat, it applies to a different animal companion or bonded mount. If a paladin selects this feat, his bonded mount loses the celestial template for the new one.
Some adjustments...
Airborne Mount
Who never desired a flying steed?
Prerequisites: Bonded mount or animal companion class ability (an animal companion must be trained to serve as a mount), effective class level 5th.
Benefit: The bonded mount or animal companion acquires the airborne simple template (from The Genius Guide to Air Magic). It can grow batlike, dragonlike or birdlike wings, suiting the master's desire. If you have more than one animal companion or bonded mount, choose one to receive this benefit. If you lose or dismiss an animal companion or bonded mount, you may apply this feat to the replacement creature.
Special: You may select this feat more than once. The effects do not stack. Each time you take the feat, it applies to a different animal companion or bonded mount. If a paladin selects this feat, his bonded mount loses the celestial template for the new one.
Winged Mount
Your airborne mount acquires new special abilities.
Prerequisites: Bonded mount or animal companion class ability (an animal companion must be trained to serve as a mount), effective class level 11th, Airborne Mount feat.
Benefit: The bonded mount or animal companion loses the airborne template and acquires instead the half-celestial (for good characters), half-fiend (for evil characters) or half-dragon template. If you have more than one airborne animal companion or bonded mount, choose one to receive this benefit. If you lose or dismiss an animal companion or bonded mount, you may apply this feat to the replacement creature.
Special: You may select this feat more than once. The effects do not stack. Each time you take the feat, it applies to a different animal companion or bonded mount. An animal companion or bonded mount can't benefit from both this feat and the Boon Companion feat.