Well, "writing off" the costs is not worth too much when you don't have any profits! Yes, the airlines can -- and do -- deduct the cost of operating their aircraft. If they carry FAMs for free, they cannot sell those seats and might get less revenue (this is debatable). But without profits, deductions are worthless. Tax savings are zero.
The congressional testimony to which I referred was a couple of years ago. Things may have changed. But I would be really amazed to learn that the FAM service is paying top dollar for its seats. At best, they would pay government fares. As a former long-time government employee, I know how low those are!
Can any airlines employees shed light on this issue? Does the FAM service pay for its seats now?
Bruce