Abstract: A system for controlling the thickness and distribution of a coating applied to a moving substrate includes a pair of "air knives" which discharge pressurized fluid onto a moving substrate as it emerges from a coating bath to screed excess coating from the substrate and leave a coating deposit having a desired thickness and distribution. Each air knife has a plenum chamber which supplies pressurized fluid to a pair of nozzle lips that define an elongated nozzle opening. Fluid flow influencing devices are provided between the plenum and the nozzle lips of each air knife. The flow influencing devices preferably include a baffle plate, a screen assembly, a shutter plate, and a vane assembly. The baffle plate and the screen assembly help assure that a laminar, equally pressurized flow is supplied to the shutter plate.