  We present a spectro-astrometric survey of molecular gas in the inner regions
of 16 protoplanetary disks using CRIRES, the high resolution infrared imaging
spectrometer on the Very Large Telescope. Spectro-astrometry with CRIRES
measures the spatial extent of line emission to sub-milliarcsecond precision,
or <0.2 AU at the distance of the observed targets. The sample consists of
gas-rich disks surrounding stars with spectral types ranging from K to A. The
properties of the spectro-astrometric signals divide the sources into two
distinct phenomenological classes: one that shows clear Keplerian astrometric
spectra, and one in which the astrometric signatures are dominated by gas with
strong non-Keplerian (radial) motions. Similarly to the near-infrared continuum
emission, as determined by interferometry, we find that the size of the CO line
emitting region in the Keplerian sources obeys a size-luminosity relation as
$R_CO L_*^0.5. The non-Keplerian spectro-astrometric signatures are likely
indicative of the presence of wide-angle disk winds. The central feature of the
winds is a strong sub-Keplerian velocity field due to conservation of angular
momentum as the wind pressure drives the gas outwards. We construct a
parametrized 2-dimensional disk+wind model that reproduces the observed
characteristics the observed CO spectra and astrometry. The modeled winds
indicate mass-loss rates of >10^-10 to 10^-8 Msol/yr. We suggest a unifying
model in which all disks have slow molecular winds, but where the magnitude of
the mass-loss rate determines the degree to which the mid-infrared molecular
lines are dominated by the wind relative to the Keplerian disk surface.
