In the coming years, the skies are going to be increasingly dotted with all types of uncanny aircraft. But interstellar travelers won't be piloting these vehicles. What is likely to be zipping across your airspace are identified flying objects of the terrestrial kind. They are better known as Unmanned Aerial Vehicles (UAVs) and these robotic policing craft are loaded with high-tech sensors and other snooping gear. Homeland Security head, Tom Ridge, has said his department is considering the use of UAVs to monitor U.S. borders "very seriously" and plans to work with the Department of Defense in evaluating the robot planes for this task by year's end. Robert Bonner, Department of Homeland Security's commissioner of customs and border protection, told Congress in June that UAVs could offer a unique service. "UAVs may well be a good answer for stretches of the border that do not have enough sensor protection," he said. Spotting border penetration by terrorists, or catching a view of illegal immigrants, are among feasible duties for UAVs, their surveillance and interception capabilities having been showcased in Afghanistan and Iraq. However, Unidentified Flying Object (UFO) study groups say that one by-product in using any UAV the expected rise in flying saucer sightings. To the uneducated eye, UAVs just look weird.