Flying, yes. Squirrel based, no.
http://www.nintendoworldreport.com/news/53789/lego-mario-set-adds-power-up-outfits-for-mario
It won't just be regular Super Mario in this summer's LEGO set, unless you want it to.
LEGO and Nintendo have announced a series of "Power Up Packs" that will allow for the replacing of the classic Mario outfit with four power-up based designs. The packs will be available for Fire, Propeller, Builder, and Cat Mario.
The Power Up Packs will be available on August 1 and can be preordered from the official LEGO store and Walmart in the US.