WASHINGTON — Leaps in unmanned aircraft technology have military authorities clamoring to use drones for everything from coastal patrols and border surveillance to tracking natural disasters. But fears of midair collisions are slowing any broad expansion of their domestic use.

Federal Aviation Administration officials made it clear in a recent closed government conference that until the pilotless aircraft gain the high-tech ability to sense and avoid commercial aircraft and other airborne objects, the government is unlikely to allow them to operate much more freely in congested airspace.

For the military, it's a frustrating limitation. For the FAA, it's a matter of safety.

During the Northern California wildfires last summer, the Air Force, Navy and NASA each offered to launch unmanned systems to track the flames, identify hot spots and determine where the fires were likely to move. But due to FAA guidelines, only a single drone could fly in the region at one time.

NASA's Ikhana — a variant of the military's Predator unmanned aircraft — got the first call. Global Hawks operated by the Navy and Air Force were also flown, but at separate times from the NASA drone.

Military officials raised the firefighting incident as an example of expanded drone uses during a two-day summit at U.S. Northern Command in Colorado Springs, Colo., late last month. At the meeting, up to 100 senior leaders from at least 10 government agencies tried to resolve some of the problems that restrict the use of unmanned aerial vehicles, or UAVs, in American airspace.

"I realize that (the Defense Department) has been very comfortable with using UAVs at will in Iraq and Afghanistan airspace," said John Allen, director of Flight Standards Service for the FAA, during an interview with The Associated Press. "And there is a reality check when they bring them stateside and try to utilize them and realize there are restrictions."

FAA spokeswoman Laura Brown said the agency expects to have a plan covering drone use in place next year, and will try to work with military and other officials in the coming fire and hurricane seasons to perhaps allow some type of staggered flights if needed.

The increasing demand for drones raises complex questions because the aircraft are piloted remotely, often from thousands of miles away. Their intrusion into crowded air traffic lanes would require constant monitoring and coordination to avoid planes, tall buildings and possibly each other.