  We investigate the possibility of guiding stable ultraslow weak-light bullets
by using Airy beams in a cold, lifetime-broadened four-level atomic system via
electromagnetically induced transparency (EIT). We show that under EIT
condition the light bullet with ultraslow propagating velocity and extremely
low generation power formed by the balance between diffraction and nonlinearity
in the probe field can be not only stabilized but also steered by the assisted
field. In particular, when the assisted field is taken to be an Airy beam, the
light bullet can be trapped into the main lobe of the Airy beam, propagate
ultraslowly in longitudinal direction, accelerate in transverse directions, and
move along a parabolic trajectory. We further show that the light bullet can
bypass an obstacle when guided by two sequential Airy beams. A technique for
generating ultraslow helical weak-light bullets is also proposed.
