If a hijack was confirmed, procedures called for the hijack coordinator on duty to contact the Pentagon's National Military Command Center (NMCC) and to ask for a military escort aircraft to follow the flight, report anything unusual, and aid search and rescue in the event of an emergency.
Once a hijacking is confirmed the Pentagon's National Military Command Center (NMCC) is supposed to be notified so they can order a military escort aircraft to follow the flight and report on anything suspicious.