To be eligible for Space-A flights, Veterans must have a permanent and total service-connected disability rating. Flights are typically free of charge, but you should contact your closest Air Mobility Command, or AMC, passenger terminal or the terminal at the location you intend to depart from for specific information.
Most terminals have a Facebook page where they post flight information, including their 72-hour flight schedule.
Read more at: https://www.blogs.va.gov/VAntage/60642/eligibility-disabled-veterans-space-available-flights/
Air Mobility Command: https://www.amc.af.mil/Home/AMC-Travel-Site/AMC-Space-Available-Travel-Page/