Enrico Valdinoci Plane-like minimizers in periodic media: jet flows and Ginzburg-Landau-type functionals (605K, PostScript) ABSTRACT. This paper is divided in three parts. In the first part, we consider a functional related with models for jets of fluids, invariant under integer translations. In the second part, we deal with more general Ginzburg-Landau-type functionals. We prove that these functionals have plane-like quasi-periodic minimizers. In the third part, we show how the results above contain, as a limit case, the recent Theorem of Caffarelli and de la Llave.