Lighting fixtures are designed to perform the primary function of providing given lumen output as per the requirement. The major components of the lighting fixtures include LED unit, Drivers, Heat sink, and LED casing. With the advent of new technologies in the field of IoT, Wireless communications, etc., lighting fixtures are seen as potential devices that can integrate these technologies. One of the function that is gaining interest in present days is providing air circulation through the lighting fixture, thereby, replacing or eliminating the air return units presently used in the false ceilings. Slots with specific areas are provided at various locations in the fixture to create the airflow return path through the fixture. Though there has been extensive research in the field of thermal management of luminaries using CFD, studies pertaining to airflow return are relatively scarce. Present studies describe the CFD methodology for predicting pressure drop across the fixture for the given mass flow rate. Ansys-Fluent is used as a solver to model the airflow return through lighting fixtures for various governing parameters. A comparison is made with the actual test results and a mathematical model is then formulated for predicting the pressure drop for a given slot area and mass flow rate.