Spacetime Algebra (STA) provides unified, matrix-free spinor methods for rotational dynamics in classical theory as well as quantum mechanics. That makes it an ideal tool for studying particle models of zitterbewegung and using them to study zitterbewegung in the Dirac theory. This paper develops a self-contained dynamical model of the electron as a lightlike particle with helical zitterbewegung and electromagnetic interactions. It attributes to the electron an electric dipole moment oscillating with ultrahigh frequency, and the possibility of observing this directly as a resonance in electron channeling is analyzed in detail. A modification of the Dirac equation is suggested to incorporate the oscillating dipole moment. That enables extension of the Dirac equation to incorporate electroweak interactions in a new way.