There is a widespread use of drones due to their rising applications that have come into fruition in the military, safety surveillance, agriculture, smart transportation, shipping, and delivery of packages in our Internet of Things global landscape. However, there are security-specific challenges with the authentication of drones while airborne. The current authentication approaches, in most drone-based applications, are subject to latency issues in real-time with security vulnerabilities for attacks. To address such issues, we introduce a secure authentication model with low-latency for drones in smart cities that leverages blockchain technology. We apply a zone-based architecture in a network of drones, and use a customized decentralized consensus, known as DDPOS (Drone-based Delegated Proof of Stake), for drones among zones in a smart city that does not require re-authentication. The proposed architecture aims for positive impacts on increased security and reduced latency on the Internet of Drones (IoDs). Moreover, we provide an empirical analysis of the proposed architecture compared to other peer models previously proposed for IoDs to demonstrate its performance and security authentication capability. The results clearly show that not only does the proposed architecture have low packet loss rate, high throughput, and low end-to-end delay in comparison to peer models, but also can detect 97.5% of attacks by malicious drones while airborne.