Recently, visual odometry (VO) has experienced a rapid growth, which makes it viable for a range of applications. This survey paper attempts to provide a timely and comprehensive review of this field, focusing specifically on micro aerial vehicles (MAVs), with monocular, stereo or RGB-D cameras onboard. In this survey, the milestones in the development of VO will be reviewed, followed by an illustration of its general workflow, the commonly used datasets. The survey is concluded by an overall discussion.