There is no subsidy. It says right in the law that they can be charged the comensurate rate for baggage. Or the cost of an extra ticket in the case of a cello.

There is no subsidy. It says right in the law that they can be charged the comensurate rate for baggage. Or the cost of an extra ticket in the case of a cello. The only thing it enforces is that they can't be gouged to pay extra merely for bringing a musical instrument aboard.