Glider

A glider is a customization feature used in Mario Kart 7 and Mario Kart 8. After driving over a blue Boost Pad with arrows, the selected glider automatically deploys, allowing players to float across gaps or over a portion of a track. Gliders only affect the weight and acceleration stat, along with the hidden air speed and air handling stat.

Mario Kart 7
Gliders first appear in Mario Kart 7. They may affect the weight or acceleration, or even the air speed and air handling. If players brake or get hit with an item while gliding, the glider retracts and the player falls to the ground.

All tracks in the game, excluding Rosalina's Ice World, N64 Luigi Raceway,  GCN Daisy Cruiser, and  SNES Rainbow Road, utilize the glider.

Mario Kart 8
Gliding returns in Mario Kart 8, and functions exactly like it did in Mario Kart 7, though the glider can no longer be retracted.

The only tracks in the game that don't make use of gliding are Toad Harbor, GCN Dry Dry Desert,  SNES Donut Plains 3, SNES Rainbow Road, Mute City, Dragon Driftway, Excitebike Arena,  GCN Yoshi Circuit, and  Wii Wario's Gold Mine.

Trivia

 * The Super Glider, Peach Parasol, Flower Glider, Paraglider/Parafoil, and Gold Glider are the only gliders to appear in both games.