  With the discovery of the binary black hole coalescence GW150914, the era of
gravitational-wave astrophysics has started. Gravitational-wave signals emitted
by compact binary coalescences will be detected in large number by LIGO and
Virgo in the coming months and years. Much about compact binaries is still
uncertain, including some key details about their formation channels. The two
scenarios which are typically considered, common envelope evolution and
dynamical capture, result in different distributions for the orientation of the
black hole spins. In particular, common envelope evolution is expected to be
highly efficient in aligning spins with the orbital angular momentum. In this
paper we simulate catalogs of gravitational-wave signals in which a given
fraction of events comes from common envelop evolution, and has spins nearly
aligned with the orbital angular momentum. We show how the fraction of aligned
systems can be accurately estimated using Bayesian parameter estimation, with 1
$\sigma$ uncertainties of the order of 10% after 100-200 sources are detected.
