A new market-based decentralized algorithm is proposed for task assignment of multiple unmanned aerial vehicles in network environment with limited connectivity. In particular, the cooperative timing mission which cannot be performed by a single vehicle is considered. The proposed market mechanism consists of four intuitive phases to allocate coalitions with a greedy approach. Convergence and scalability analysis shows that the proposed algorithm has a polynomial-time complexity. The upper bound of the amount of communication is also derived. Numerical results support the scalability with respect to runtime and communication. The suppression of enemy air defense scenario is introduced as a numerical example to demonstrate the performance of the proposed algorithm.