THE TIMELINE for Amazon's flying delivery service has been pushed back after one drone caused a brush fire. Jeff Bezos, Amazon founder and CEO, has long been vocal about his plan for creating a fleet of drones to deliver Prime packages in 30 minutes. However, despite spending more than $2 billion on the project, Amazon is still not in a place to launch the planned delivery system. In fact, a Bloomberg investigation found that the service is plagued by technical challenges and safety concerns. Furthermore, drones have crashed in test runs, and have even been the cause of a brush fire that spanned 25 acres. Reports found that last year, five delivery drones crashed at Amazon's test site in Oregon, with one causing the fire.