  We introduce and analyze a virtual element method (VEM) for the Helmholtz
problem with approximating spaces made of products of low order VEM functions
and plane waves. We restrict ourselves to the 2D Helmholtz equation with
impedance boundary conditions on the whole domain boundary. The main
ingredients of the plane wave VEM scheme are: i) a low frequency space made of
VEM functions, whose basis functions are not explicitly computed in the element
interiors; ii) a proper local projection operator onto the high-frequency
space, made of plane waves; iii) an approximate stabilization term. A
convergence result for the h-version of the method is proved, and numerical
results testing its performance on general polygonal meshes are presented.
