Helicopter Yoshi

A Yoshi Helicopter (sometimes known as the Yoshi-Copter) was a form Yoshi could become in Super Mario World 2: Yoshi's Island. Yoshi had to touch a Morph Bubble with a helicopter inside of it to become this.

In this from Yoshi could fly around the level for a short time. The form returned in Yoshi's Island DS.

In Mario Kart: Double Dash, a Yoshi Helicopter appeared in Baby Park and Yoshi Circuit, however it was not a form, it was an actual vehicle.