Would fighting on top of a floating disc count as Mounted Combat or Flying Combat?

Was looking into magic Trick for Floating Disk and had some questions about how this ability changes things

Disk Rider (Fly 3 ranks): You can ride atop any floating disk you create, so long as it has the capacity to support your weight. This grants you a fly speed of 30 feet (average), but the disk cannot move itself or you more than 5 feet above the ground at any time.

Mechanically, would a Wizard riding on top of the Disk count as riding a mount or as flying combat, for the purpose of feats + mechanics?