Sec. 121.541 - Operations schedules: Domestic and flag
In establishing flight operations schedules, each certificate holder conducting domestic or flag operations shall allow enough time for the proper servicing of aircraft at intermediate stops, and shall consider the prevailing winds en route and the cruising speed of the type of aircraft used. This cruising speed may not be more than that resulting from the specified cruising output of the engines.
[Doc. No. 28154, 61 FR 2613, Jan. 26, 1996]