41 CFR § 301-10.140
May I use a foreign air carrier if the service is preferred by or more convenient for my agency or me?
June 9, 2020
No. You must use U.S. flag air carrier service, unless you meet one of the exceptions in §301-10.135, §301-10.136, or §301-10.137 or unless foreign air carrier service is deemed a matter of necessity under §301-10.138.