The 5th U.S. Circuit Court of Appeals has ruled that an employer may require an hourly employee to take an unpaid meal break while traveling for work. Two conditions must be met; the employee is relieved of any duties during the break and the time qualifies as a bone fide meal period under the FLSA. This ruling came from a lawsuit filed by U.S. ICE officers.
See "Court rules that employers can require unpaid meal breaks during employee travel", Marc Alifanz and John Stellwagen, SHRM, September 29, 2021