A well-known benefit that is known in military circles but often not known among the general public is the ability to travel at little or no cost for military Servicemembers and their dependents. It is a program that Congress created many years ago to help show appreciation for the service of military members, to allow military Servicemembers to travel on different military vehicles and aircraft on a space available basis. The program is called Space Available, or Space A, and it is an effective type of travel for military Servicemembers on aircraft that extra room not filled entirely by the flight or mission.
Flying on Space Available is a method of travel that is effective, but it takes a fair amount of flexibility and patience. The method of travel involves flying on military aircraft that has extra spaces on it, so it is not possible to forecast when this type of travel will occur, but only can be accessed in many cases by patience and standing by. It is not a right, but a privilege that is available only after the needs of the military flight or mission is fulfilled. Any extra space is made available to military personnel, based on a priority access schedule and gives personnel the ability to fly for little or no actual cost. This is travel for active duty, active duty dependants or family, certain types of Reserves or National Guard members who have been mobilizing. The premise is pretty simple: you go to a specific airfield that features military flights in and out. Sometimes it is possible to pre register for certain types of flights. You can also register the day of travel, for aircraft that has space available on it. If a flight comes in and then is headed out to where you wish to go and it has available space, then you can qualify to ride along for free. It can be a very good deal, but it is not possible to predict when and where a certain flight may have extra room, you are at the mercy of the military and the extra room on flights may be constant, or it may be several hours, days or even weeks before a flight comes in with extra space on it. So flexibility, patience and the ability to wait is key for flying space available.
The program used to have a great deal of added visibility, but in the days after 9/11 it became much more security conscious. It is still possible to fly on Space Available, but the access is much more secure and it involves a lot less warning when you are flying, you have to often literally be ready to go at a moments notice.