This article is from the 2006 series of SMBZ and is no longer canon.
The Sky Pop is the plane that the heroes use to get the Omega Doomship. In SMBZ the new second version of the Sky Pop appears.
The Sky Pop is a yellow airplane that has appeared only in World 4-3 of the Chai Kingdom in Super Mario Land. It can fire missiles with unlimited ammunition. Mario uses it primarily to defeat Chickens, Biokinton, Roketons, and Tatanga. After defeating Tatanga, Mario flies off with Princess Daisy in a different Sky Pop that is Jet-Powered and has two Pilot Seats. Another "Sky Pop" makes a brief appearance in the end of Wario Land: Super Mario Land 3, when Mario steals the golden statue of Princess Toadstool. However, this Sky Pop was a helicopter instead of an airplane.
The second one is seen in Episode 8. It is still a prop plane, but has two seats now instead of being a single seater. The speed of the plane has increased as well as the maneuverablity. It is also designed to fire missiles. It was last seen landing on the Omega Doomship after which Luigi and Yoshi bailed out of it to fight against the Koopatrols.