41 C.F.R. § 301-10.110 – Requirement to use contract City Pair Program fare.

(a) Employees of an “agency” as defined in § 300-1.1 of this subtitle must use a contract City Pair Program fare for scheduled air passenger transportation service unless specific exceptions exist in § 301-10.111.
(b) When a carrier offers both a lower-cost capacity-controlled coach class contract fare (_CA) and an unrestricted coach class contract fare (YCA), employees must use the lower-cost fare when it is advantageous and meets mission needs.
(c) Employees of the Government of the District of Columbia, except the District of Columbia Courts, are not eligible to use contract City Pair Program fares.