Different models for single droplet fragmentation have been assessed for different initial accelerations in the bag and sheet-thinning regimes. The predictions have been compared to high-speed-video sequences where a single droplet is injected in a cross-flow of air. It is concluded that the modeling of the temporal evolution of the breakup process is important. This includes modeling of the droplet drag before and after droplet initiation as well as a realistic breakup time. Furthermore, if the breakup criterion is based on a critical deformation instead of a critical Weber number, predictions of trajectories are improved for transient aerodynamic loadings.