Internet of Things (IoT) promotes the awareness about our world and eases human life. In IoT, machine-to-machine (M2M) communications empowers machine-type-devices (MTDs) to cooperatively exchange information and perform actions. Current M2M communications primarily leverages cellular networks to provision reliable services. When a disruptive disaster destroys the local cellular infrastructure, unmanned aerial vehicle mounted base stations (UBS) can be deployed to assist rescue by facilitating M2M communications among the human portable/wearable MTDs (HMTDs). The UBS network access and resource allocation scheme is proposed to maximize the number of HMTDs to establish communications. We have validated the proposed scheme through extensive simulations.