14 CFR § 271.6
Profit element
July 13, 2020
The reasonable return for a carrier for providing essential air service at an eligible place generally will be set at a flat percentage, typically 5 percent of that carrier's projected operating costs as established under §271.4, plus any applicable interest expenses on flight equipment.
[ER-1398, 49 FR 49846, Dec. 24, 1984, as amended at 60 FR 43524, 43525, Aug. 22, 1995]