This paper describes initial work on untethered microscale flying structures as a platform for new class of aerial MEMS microrobots. We present and analyze both biomimetic structures based partially on wing designs of smallest flying insects on Earth, as well as stress-engineered structures powered by radiometric (thermal) forces. The latter devices, also called MEMS Microfliers are 300 μm × 300 μm × 1.5 μm in size, and are fabricated out of polycrystalline silicon. A convex chassis, formed through a novel in-situ masked post-release stress-engineering process, ensures their static inflight stability. High-speed optical micrography was used to image these MEMS microfliers in mid-flight, analyzing their flight profile.