The prospect of another year of massive U.S. wildfires has the top Democrat on the Senate energy panel worried that too much bureaucratic competition could hamper the promising use of federal drones in firefighting.

Sen. Maria Cantwell (D-Wash.) said at a June 5 committee hearing on wildfire threats that the the Agriculture Department needs to avoid reinventing the wheel in its fledgling effort to use drones to combat wildfires. Instead, it should collaborate closely with the Interior Department, which...