Understanding the aerodynamic characteristics of flapping and plunging wings at low Reynolds numbers is necessary for advancing Micro Air Vehicle research and development. The flow fields around a variety of wings were investigated with Particle Image Velocimetry and hydrogen bubble flow visualization. The effects of reduced frequency, angle of attack, and wing size and shape were analyzed using the acquired data. Vortex shedding begins earlier at higher angles of attack and at lower reduced frequencies. The wing produces thrust via a jet wake.