More sponsored content has been added to Super Mario Maker with the release of the Southwest Air Adventure course.
The Mystery Mushroom containing the costume is located in the level which upon completion allows the player to use the monochrome costume in other levels of the game.
It doesn't fly, but it comes with sound effects.
Dataminers found the Sky Pop costume back in December.
Small images of the level and costume pulled from the Southwest Airlines blog are posted below.
Thanks, Nintendo Life.