Toad Express

Peach's Plane is a pink plane owned by Peach. Mario, Peach, Toadsworth and some Toads used this plane to get to Isle Delfino in Super Mario Sunshine. The plane landed in Delfino Airstrip. It came to a screeching stop, as strange Goop filled the ground.

In Mario & Luigi: Superstar Saga, Peach uses this plane again to get to the Beanbean Kingdom. However, the Beanbean International Airport is full of Piranha Plants and Mom Piranha, so the plane cannot land. Mario and Luigi get rid of the Piranhas so Peach's Plane can safely land. The plane is also seen in the ending of the game.

Mario Golf: Advance Tour gives it a small cameo, when Neil and Ella are brought to the Mushroom Kingdom via the plane.

Inside of the plane
Inside of the plane, there appears to be 4 Mushroom seats. There are blue stars on a white background in it.

Trivia
The Design of Peach's Plane used in Super Mario Sunshine appears to be based on certain real-world Flying Boats and STOL Aircraft such as the Antonov An-72, PBY Catalina, Martin P5M Marlin, Yokosuka H5Y, and Kawanishi H6K while the one in Mario & Luigi: Superstar Saga is more based on 'Jumbo Jet' Aircraft such as the Boeing 747.