That's especially true for members of the TSA, which lost one of its own Friday and had two others wounded.
The federal agency's chief, John Pistole, is heading to Los Angeles on Saturday. Before he left, he sent a message to his employees thanking them for their good work and support for each other.
"Together, we will get through this," Pistole wrote. "Our faith will guide us and our professionalism will ensure our ability to carry out our mission."