To satisfy the requirements of flow drag measurement in a wind tunnel experiment and airspeed monitoring of aircrafts in a complex electromagnetic environment, a differential-pressure fiber-optic airflow sensing system based on white-light interferometric technology was developed to perform relevant experimental investigations. The proposed system comprises a differential-pressure fiber-optic airflow sensing probe and a miniaturized white-light interferometric interrogator, which realizes synchronous high-speed, high-precision differential-pressure measurement. The sensing probe realizes single-channel differential-pressure sensing and can detect flow drag by obtaining the difference between the surface pressure of the target measurement object and the static pressure in the flow field. In addition, the sensing probe can be coupled with a pitot tube to measure flow velocity. The white-light interferometric interrogator comprises a wavelength scanning laser, a field-programmable gate array module for control and acquisition, and a photoelectric detector. The proposed system was used to measure and analyze the classical model of flow around a circular cylinder in wind tunnel testing. The results are similar to those obtained using a standard multichannel electronic pressure transducer. The proposed fiber-optic sensing system uses only optical fiber as the medium to sense and transmit signals, which can effectively resist electromagnetic interference. Thus, the proposed system enables using the optical method to accurately analyze the flow drag in an airflow field in a strong electromagnetic interference environment and has a practical potential application in future aerodynamics research and in-flight monitoring.