1. From the numerical values of vibration frequencies and logarithmic decrements determined with air bearings of various types over a wide range of bearing height and a wide range of air pressure in the bearing cavity under various modes of dynamic load, one can estimate the effect of such bearings as aid for dynamic testing of structures on the vibration characteristics of the latter. 2. The extent to which air bearings affect the vibration characteristics of tested objects depends on the relation between load capacity of the air bearing and weight of the tested object as well as on the intrinsic damping in the object. Therefore, structures must be tested on air bearings with maximum load capacity only slightly above the weight of the structures and especially so when the intrinsic damping in the structure is small.