An air velocity indicator and control device is provided for use with pneumatic distribution systems used in air seeders that pneumatically discharge agricultural product to the ground, seedbed, or furrow. The air velocity indicator and control device includes a tubular housing, extending between an inlet and an outlet, and pivotally housing a deflectable plate that actuates in response to encountering an airflow entrained with agricultural product. A magnitude of deflection of the deflectable plate, corresponding to airflow velocity, can be displayed through an indicator assembly. This enables a user to identify velocity variances and differentials within the air seeder and make corrective adjustments. In some implementations, multiple air velocity indicator and control devices are ganged together with deflectable plates that pivot in unison with each other. The relative angle of fixation of the deflectable plates, upon the pivot pin, can be adjusted to permit airflow tuning as needed.