41 CFR § 301-10.111
When may I use a reduced group or charter fare?
June 9, 2020
You may use a reduced group or charter fare when your agency has determined, on an individual case basis prior to your travel, that use of such a fare is cost effective. Chartered aircraft are subject to the same rules as Government aircraft, and agencies in the executive branch of the Federal Government are subject to the requirements of Office of Management and Budget (OMB) Circular A-126 and 41 CFR part 101-37 in making such cost effectiveness determinations.
[FTR Amdt. 108, 67 FR 57964, Sept. 13, 2002]