The aerodynamic breakup of water and fuel droplets has received considerable attention over the years. Some data exist on the effects of surface tension and to a lesser extent normal viscous and non-Newtonian fluid properties. The main focus of attention has usually been on droplet behavior, and less attention has been paid to jets and ligaments in shear flows. In the present article, new photographic results are presented of the breakup of fuel ligaments in transverse shock flows, and the influence of viscosity and non-Newtonian properties of fluids are illustrated. The high-resolution images show the development of features reminiscent of Rayleigh-Taylor instabilities, along the length of the ligament, with wavelengths dependent on the fluid viscosity. These instabilities lead to the development of "stripping centers." The technique is seen as one suitable for a more detailed investigation of the development of instabilities as a function of the physical properties of liquids.