  We study the accretion/ejection processes (i.e. disc/jet coupling) in the
neutron star X-ray binary Aquila X-1 via a multi-wavelength approach. We use in
the radio band the publicly available VLA archive containing observations of
the object between 1986-2005, in the X-ray band the archival RXTE data (PCA and
HEXTE) between 1997-2008, and in optical (R band) observations with the SMARTS
recorded between 1998-2007. In the combined data set we find three outbursts
for which quasi-simultaneous radio, optical (R band) and X-ray data exist and
focus on them to some extent. We provide evidence that the disc/jet coupling in
Aquila X-1 is similar to what has been observed in black hole X-ray binaries,
at least from the point of view of the behaviour in the hardness-intensity
diagrams (the hysteresis effect included), when the phenomenology of the jet is
taken into account. Although based on a very small number of observations, a
radio/X-ray correlation seems to exist for this system, with a slope of
alpha=0.40 +/- 0.07 (F_{radio} \propto F_{X}^{alpha}), which is different than
the slope of alpha=1.40 +/- 0.25 found for another atoll source, 4U 1728-34,
but interestingly enough is relatively close to the values obtained for several
black hole X-ray binaries. No significant correlation is found between the
radio and optical (R band) emissions. We also report a significant drop in the
radio flux from Aql X-1 above an X-ray flux of ~ 5 X 10^{-9} erg cm^{-2}
s^{-1}. This behaviour, also reported in the neutron star X-ray binary 4U
1728-34, may be analogous to the suppression of radio emission in black hole
X-ray binaries in bright, soft X-ray states. It suggests that from this point
of view neutron star X-ray binaries can mimic the behaviour of black hole X-ray
binaries in suppressing the jet in soft/disc-dominated X-ray states.
