Imagine re-making the components of a cell tower, hanging them from a self-guided robot balloon, and sending the whole thing up to 20km above the earth, and achieving a coverage area of 5,000 square km instead of the usual 300 square km.
That's Project Loon, created at X (the crazy idea part of Google), now graduated as independent businesses within the Alphabet company (which is the umbrella company over Google). Let me know if you need a company organizational chart to follow all that. The tech itself isn't this confusing.
The balloons already worked in Puerto Rico. An early contract has been signed with Kenya for more coverage in rural areas.
Imagine not needing cell towers to cover a rural area. Imagine positioning them to manage dead spots, or quickly redeploying them when a dead spot is identified. Imagine really good cell signal in even sparsely populated areas.