Fisher House Foundation, a nonprofit known for its network of comfort homes on the grounds of the military's major medical centers, partners with airlines to provide travel for wounded or injured service members to take leave from military hospitals, and for their families to visit them at their bedside through the use of donated miles.

For further details:
'Operation Hero Miles' Expands to Families of Wounded Troops (DefenseLINK)
Fisher House Explains Rules for Free Airline Tickets (DefenseLINK)