Photos: Unmanned vehicles take to air, land and sea

A long-endurance, high-altitude Predator B drone like this one started patrolling the southwestern border of the United States, under the direction of U.S. Customs and Border Protection officials, in 2005.

The agency now owns two of the General Atomics-made UAVs and plans to add two more this fall, designating one to keep watch over the nation's northern border. A few more may be acquired next year as well.

Operating UAVs in the domestic airspace has proved controversial among the piloting community, but Michael Kostelnik, assistant commissioner of the CBP's air and marine unit, attempted to assuage those concerns in his AUVSI symposium speech. Sending the crafts aloft, he said, is about protecting "you and your families."