A brief review of some current efforts to fully understand ultrasonic wave propagation in air is presented, along with some miscellaneous items of value in an intelligent manufacturing environment. The use of an airborne ultrasonic sensor can be a valuable tool in an intelligent manufacturing environment as long as the physics of wave propagation is thoroughly understood. Beam divergence, attenuation, presence of side lobes, ability to control interference patterns, etc., and the ability to improve signal-to-noise ratio can add significantly to creative use of ultrasonic sensors in manufacturing. Dimensional checks of a product, position measurement of various system hardware, and product quality measurements are all possible with airborne ultrasonic sensors. Basic tools for accomplishing these sensing activities are discussed.