  We consider the dynamics of systems of self propelling particles with
nonholonomic constraints. A continuum model for a discrete algorithm used in
works by T. Vicsek et al. is proposed. For a case of planar geometry the finite
flocking behavior is obtained. The circulation of the velocity field is found
not to be conserved as a consequence of the nonholomicity. The stability of
ordered motion with respect to noise is discussed. An analogy with the kinetics
of charges in superconductors is noted.
