Nintendo is still not being any more specific than "Spring 2014," but when Mario Kart 8 gets here, Bowser, Mario, Yoshi and all the rest will be tearing-arse around airport and cloudtop courses with a new buggy-type vehicle. See it in the latest trailer here.
In addition to the new courses and car, the trailer features new driver characters, including Baby Mario, Baby Luigi, and Rosalina, who also appeared in a Smash Bros. trailer today.
Rosalina and various "Baby" Nintendo characters, like Baby Mario and Baby Luigi. New course settings include an airport, the desert and high in the clouds, and vehicles include UFOs, four-wheel ATV buggies, standard karts and bikes.