  In this paper we derive explicit formulas for the densities of Levy walks.
Our results cover both jump-first and wait-first scenarios. The obtained
densities solve certain fractional differential equations involving fractional
material derivative operators. In the particular case, when the stability index
is rational, the densities can be represented as an integral of Meijer G
function. This allows to efficiently evaluate them numerically. Our results
show perfect agreement with the Monte Carlo simulations.
