Appalling moment United passenger punches gate agent and knocks him out

A disgruntled United Airlines passenger punched a gate agent in the face which knocked the airport staffer to the ground, leaving him unconscious. The violent outburst happened last Thursday evening at 5:30pm at Virginia's Dulles International Airport by gate D12 when Christopher Stuart Crittenden, a 54-year-old man from Frederick, Maryland, suddenly lost control and lashed out. Video footage, which has since gone viral, captures the moment as Crittenden strides toward the gate agent and without warning swings his fist striking the unsuspecting employee squarely in the face. The force of the impact was so severe the agent instantly fell to...