The Micromechanical Flying Insect (MFI) Project Publications state: The goal of the Micromechanical Flying Insect (MFI) project is to develop a 25 mm (wingtip-to-wingtip) device capable of sustained autonomous flight. The MFI is designed based on biomimetic principles to capture some of the exceptional flight performance achieved by true flies.
The high performance of true flies is based on large forces generated by non-steady state aerodynamics, a high power-to-weight ratio motor system, and a high-speed control system with tightly integrated visual and inertial sensors. Our design analysis shows us that piezoelectric actuators and flexible thorax structures can provide the needed power density and wing stroke, and that adequate power can be supplied by lithium batteries charged by solar cells.
The MFI project started in May 1998. In the first three years of this MURI grant, research concentrated on understanding fly flight aerodynamics and on analysis, design and fabrication of MFI actuators, thorax and wings. In August 2001, our MFI prototype (with 1 wing) showed thrust forces on a test stand. In September 2002, we switched our fabrication from folded stainless steel to carbon fiber. In March 2003 we demonstrated 500 microNewtons of lift from a single wing on a test stand. Since March 2003, we have been working on reducing weight, increasing actuator power density, increasing airframe strength, and improving wing control. 
MAVs are also excellent tools for law enforcement, but as noted in previous articles, powermongers always use technology for evil purposes. Big Brother will build numerous fleets of MACs to spy on you. Big Brother has already built hundreds of different models of MAVs. Eventually he will have millions of these pesky bugbots swarming over the earth watching everything everyone does. Some of them will be killer bugbots that will fire micro-poison darts.