  We report on the modulation of indirect excitons (IXs) as well as their
transport by moving periodic potentials produced by surface acoustic waves
(SAWs). The potential modulation induced by the SAW strain modifies both the
band gap and the electrostatic field in the quantum wells confining the IX,
leading to changes in their energy. In addition, this potential capture and
transports IXs over several hundreds of {\mu}m. While the IX packets keep to a
great extent their spatial shape during transport by the moving potential, the
effective transport velocity is lower than the SAW group velocity and increases
with the SAW amplitude. This behavior is attributed to the capture of IXs by
traps along the transport path, thereby increasing the IX transit time. The
experimental results are well-reproduced by an analytical model for the
interaction between trapping centers and IXs during transport.
