5 U.S. Code § 5733
5.U.S. Code § 5733 is about Expeditious travel. It is under Subchapter II (Travel And Transportation Expenses; New Appointees, Student Trainees, And Transferred Employees) of Chapter 57 (Travel, Transportation, And Subsistence) of Subpart D (Pay and Allowances) of Part III (Employees) of Title 5 (Government Organizations and Employees) of the Code.
The travel of an employee shall be by the most expeditious means of transportation practicable and shall be commensurate with the nature and purpose of the duties of the employee requiring such travel.