Axisymmetric computational fluid dynamics (CFD) simulations are conducted to investigate the deformation and breakup of water drops in an air stream at different Weber numbers. The type of flows considered lie in the oscillatory, the bag breakup, the stamen breakup, and the stripping breakup regimes. A fully three-dimensional simulation is first performed to justify the axisymmetry assumption used in the remaining CFD simulations. In order to keep the drop within the fixed computational domain, the shifted Eulerian adaption (SEA) method has been developed. In this method all the field values are shifted back by one mesh cell after the center of the liquid mass has moved forward by one cell, while at the same time the boundary conditions are maintained. The CFD results are compared with experimental drop breakup observations, and are used to validate a proposed modification to the Taylor analogy breakup ( TAB) model. The modifications to the original TAB model account for the nonlinear change of the drop cross section and the associated change in the drag coefficient. The validations include the critical deformation at which the drop starts disintegrating, the drop oscillation periods, as well as the normalized drop deformation at the initiation time for breakup. The CFD results show good agreement with the modified TAB model, and the breakup behavior qualitatively reflects experimental observations.