In a quiet-ish change that occurred on 9 June 2015, the eligibility requirements to use Space A travel within the Continental United States (CONUS) were extended to include the dependents of service members who are deployed for 30 days or longer. This is going to be a great benefit for families who might want to travel during deployment and can use Space A to cut costs.
Many years ago, spouses and children were not able to use Space A travel benefits within CONUS except under very limited circumstances such as emergency leave and TDY for house hunting. In recent years, the rules have been revised a few times to include dependents whose service member was deployed for a specified period of time. This recent change, to 30 days deployment for eligibility, represents the most generous CONUS Space A benefits to date.
Dependents gaining their Space A eligibility due to service member deployment will be Category IV in priority. Those requesting travel will require a memo detailing their eligibility, and a sample memo can be found at the AMC website. This definitely requires a little pre-planning to have the eligibility memo before you start the travel process.
Space A is a great way to travel at highly reduced cost if you have the patience and flexibility to wait for available flights. Before starting on your first Space A adventure, do some research to learn about the process so that you have realistic expectations. The first place to read is the Air Mobility Command webpage and SpaceA.net. There are also many smaller groups and forums that discuss Space A travel.
Interestingly, this change is one of the 15 recommendations made by the Military Compensation and Retirement Modernization Commission Recommendation Assessment. While the majority of the recommendations were about pay and health care issues, the final six issues are direct quality of life topics. It is fascinating to me how the commission worked. You might find it interesting to read about the different subjects they reviewed.