In this paper, the problem of constrained computational resources in the UAV networks to serve users in a limited coverage area for diverse applications is studied. In particular, a flexible crowd-enabled task execution solution with multiple participating UAVs over a broadband wireless local area network (WLAN) is proposed in order to achieve mobility advantages, high throughput, and low latency. Then, an incentive mechanism is developed so as to encourage UAVs to trade their unused computing resources for the cooperative task execution, while benefiting, jointly, both the task owner and the participating UAVs. We analyze the interaction for determining the offered price against the availability of the participants and the computational resource units for the task execution using a two-stage Stackelberg game. Furthermore, we derive the unique Stackelberg equilibria of the game with a simplified solution approach. Finally, we provide some insightful results to evaluate the efficacy of the proposed solution.