HILL AIR FORCE BASE -- There are a number of origins to the military greeting of saluting. One of the possible origins is from the age of chivalry when knights were all mounted and wore steel armor, which covered the body completely. When two friendly knights met it was the custom for each to raise the visor and expose his face for view by the other. This was always done with the right hand, the left being used to hold the reins. It was a significant gesture of friendship and confidence, since it exposed the features and also removed the right hand from the vicinity of a weapon (sword). 

Regardless of its origin, the salute is a symbol of greeting, of mutual respect, trust and confidence initiated by the junior in rank, with no loss of dignity on either side. Salutes are exchanged upon recognition between officers or warrant officers and enlisted members of the Armed Forces when they are in uniform. Saluting outdoors means salutes are exchanged when the persons involved are outside of a building. This applies both on and off military installations. The junior member should initiate the salute in time to allow the senior officer to return it. Superiors carrying articles in both hands need not return the salute, but should nod in return or verbally acknowledge the salute. If the junior member is carrying articles in both hands, verbal greetings should be exchanged. Salutes between individuals are not required in public gatherings, such as sporting events, meetings, or when a salute would be inappropriate or impractical. Although exchange of salutes to identifiable officers in vehicles is normally not mandatory, you are required to give this courtesy to officers in appropriately marked vehicles. These can be recognized by a General's or Colonel's rank on the front license plate. When in doubt it is always best to render a proper salute.