Yes, you may use other than coach-class accommodation on common carriers if you meet one of the criteria contained in § 301-10.123 or § 301-10.162 or you may use other than lowest first-class travel if you meet one of the criteria contained in § 301-10.183 of this Title, and are authorized to do so by your agency in accordance with § 304-5.5 of this chapter.
Code of Federal Regulations
[FTR Amdt. 2009-06, 74 FR 55151, Oct. 27, 2009]