  We consider the role of the velocity in Lorentz-violating fermionic quantum
theory, especially emphasizing the nonrelativistic regime. Information about
the velocity will be important for the kinematical analysis of scattering and
other problems. Working within the minimal standard model extension, we derive
new expressions for the velocity. We find that generic momentum and spin
eigenstates may not have well-defined velocities. We also demonstrate how
several different techniques may be used to shed light on different aspects of
the problem. A relativistic operator analysis allows us to study the behavior
of the Lorentz-violating Zitterbewegung. Alternatively, by studying the time
evolution of Gaussian wave packets, we find that there are Lorentz-violating
modifications to the wave packet spreading and the spin structure of the wave
function.
