You should read FAA rules till the end...
For there is a clear explanation there (chapter22/ paragraph 74/alinea b):
Every passenger and crewmember will be offered a bag of Pampers before take off.
American consulates are requested to buy, stock and deliver the needed number of Pampers to International Airports, according to maximum seat capacity of USA bound flights .
Government of USA has allready launched a major maritime enterprise in order to carry huge loads of Pampers to foreign countries. New plants have been built in emergency to make sure no shortage of Pampers will occur which could lead to flights cancellations.