Section 301-71.105 - Must we issue a travel authorization in advance of travel?Yes, except when advance authorization is not possible or practical and approval is in accordance with § 301-2.1, § 301-2.5, or § 304-3.13. However, the following always require advance authorization:
(a) Use of reduced fares for group or charter arrangements;(b) Payment of a reduced rate per diem;(c) Acceptance of payment from a non-Federal source for travel expenses (see chapter 304 of this title); and(d) Travel expenses related to attendance at a conference.FTR Case 2020-300-1, 87 FR 55706 , Sept. 12, 2022