41 CFR § 102-33.165 - Carrying passengers on Government aircraft.

(a) You may carry passengers only on aircraft that you operate or require contractually to be operated in accordance with the rules and requirements in 14 CFR; and

(b) For certain kinds of travel, your agency must justify passengers' presence on Government aircraft.

Note 1 to § 102-33.165:

See OMB Circular A-126 and the Federal Travel Regulation (FTR) in 41 CFR subtitle F for complete information on authorizing travel and analyzing costs before authorizing travel on Government aircraft.