The dynamics of molecularly thin liquid lubricant films in sliding and flying experiments is studied principally by scanning microellipsometry and complemented with both scanning x-ray photoelectron spectroscopy and infrared spectroscopy. Microellipsometric profiling of lubricant thickness is performed in situ, either dynamically or statically on films ranging from 1 to 10 nm. The removal of liquid polyperfluoroether lubricants from sliding and flying tracks, which includes the displacement and loss depends on film thickness, molecular weight, and chemical structure. In flying and sliding, the lubricant removal rate from monolayer films is significantly slower than from multilayer films. In flying, lubricant displacement and loss increase with a decrease in molecular weight.