14 CFR § 382.31
May carriers impose special charges on passengers with a disability for providing services and accommodations required by this rule?
July 13, 2020
(a) Except as otherwise provided in this part you must not, as a carrier, impose charges for providing facilities, equipment, or services that this rule requires to be provided to passengers with a disability. You may charge for services that this part does not require.
(b) You may charge a passenger for the use of more than one seat if the passenger's size or condition (e.g., use of a stretcher) causes him or her to occupy the space of more than one seat. This is not considered a special charge under this section.
[Doc. No. DOT-OST-2004-19482, 73 FR 27665, May 13, 2008, as amended at 78 FR 67914, Nov. 12, 2013]