AT&T plans to use drones to provide cell service at concerts. They have the idea to build cell extensions into drones and flying them. The service provider is already using drones to inspect the cell towers.
http://www.theverge.com/2016/7/13/12171974/att-cell-drones-flying-cows?utm_campaign=theverge&utm_content=chorus&utm_medium=social&utm_source=twitter