The music played in the background on Rusty's ranch is Kiefer Sutherland's own music from his country band.
The small flag (one blue star on a white background with red borders) that James takes back inside his house represents a loved one in service.
During his interview with clandestine operations head Rusty Jennings (Kiefer Sutherland), Jennings mentions rival private security companies, such as Triple Canopy and Aegis, and casually refers to "that soulless fuck-pig Erik Prince". Prince is the founder of the controversial Blackwater private military contractor responsible for the Nisour Square massacre in Baghdad in 2007.
On his first mission, James Harper (Chris Pine) uses a Nikon Coolpix P1000 for the information-gathering surveillance of his assigned target. This particular camera has the most powerful optical zoom of any fixed lens camera, a 24-3000mm (125x) ratio.
The production had difficulty shooting one scene in Los Angeles, a simple shot of Chris Pine and Ben Foster just walking down the street. Despite the simplicity of the shot, they simply couldn't get permission. However, when the police arrived to see what the problem was, they volunteered to provide security for the shot because they were big fans of Foster.