Lawmakers Fight for More Eyes Above Texas-Mexico Border.. They want more aerial surveillance for the region. There are currently four UAVs, or unmanned aerial systems, assigned to the southern border. Three are based in Arizona, and most recently, one now based in Corpus Christi is classified as a maritime unit. The bill directs the Army, National Guard and the Air National Guard to design and build a hangar on the southwest border that would house UAVs. The high-tech systems would support the National Guard, U.S. Customs and Border Protection and other law enforcement. Lawmakers say that while AZ shares less than 400 miles of border with Mexico, Texas has about three times the area to cover.