Federal Hiring Freeze Act of 2011 - Prohibits the head of an executive agency from appointing an individual to any position in such agency during a fiscal year for which the Director of the Office of Management and Budget (OMB) projects that there will be a federal budget deficit. Authorizes the President to waive such prohibition under specified circumstances, including the existence of a state of war or other vital national security concern or the need to make appointments to law enforcement positions or to the United States Postal Service (USPS).