14 CFR § 141.19
Display of certificate
July 13, 2020
(a) Each holder of a pilot school certificate or a provisional pilot school certificate must display that certificate in a place in the school that is normally accessible to the public and is not obscured.
(b) A certificate must be made available for inspection upon request by:
(1) The Administrator;
(2) An authorized representative of the National Transportation Safety Board; or
(3) A Federal, State, or local law enforcement officer.