The top one says itpicture is the actual Private Pilot "license" that "expires" on April 6, 1928. The bottom picture is a "Pilot's Identification Card" that was "issued" on April 6, 1927, without an expiration date, and accompanies the actual Private Pilot "license" in the top picturelicense.
It appears that the Pilot's Identification Card and the actual Private Pilot license were issued as a pair at the same time. Private Pilot license and Pilot's Identification Card issued on April 6, 1927, and the Private Pilot license expires on April 6, 1928. Also, I would guess that the Pilot's Identification Card does not "expire."
(highlighting is mine, picture source is from the OP's question)