A sequel to the 2012 iPad 2 case of the same name, Incipio is back with Flagship Folio for iPad Air ($70). Based heavily on the prior design, it's a hard plastic folio, covered with radio transparent faux carbon fiber material. The rear shell lacks any button coverage, leaving the buttons and ports exposed. The shell is attached to the front cover via a heavy metal hinge — arguably the coolest part of the case. With the hinge and raised ridges inside…