  We experimentally investigate the deformation and breakup of droplets
interacting with an oblique continuous air stream. A high-speed imaging system
is employed to record the trajectories and topological changes of the droplets
of different liquids. The droplet size, the orientation of the air nozzle to
the horizontal and fluid properties (surface tension and viscosity) are varied
to study different breakup modes. We found that droplet possessing initial
momentum prior to entering the continuous air stream exhibits a variation in
the required Weber number for the vibrational to the bag breakup transition
with a change in the angle of the air stream. The critical Weber numbers
$(We_{cr})$ for the bag-type breakup are obtained as a function of the
E\"{o}tv\"{o}s number $(Eo)$, angle of inclination of the air stream $(\alpha)$
and the Ohnesorge number $(Oh)$. It is found that although the droplet follows
a rectilinear motion initially that transforms to a curvilinear motion at later
times when the droplet undergoes topological changes. The apparent acceleration
of the droplet and its size influence the critical Weber number for the bag
breakup mode. The departure from the cross-flow arrangement shows a sharp
decrease in the critical Weber number for the bag breakup which asymptotically
reaches to a value associated with the in-line (opposed) flow configuration for
the droplet breakup.
