Fair Taxes for Seniors Act of 2011- Amends the Internal Revenue Code to provide a one-time increase (from $250,000 to $500,000, or from $500,000 to $1 million for married taxpayers filing joint returns) in the exclusion of gain from the sale of a principal residence by a taxpayer who has attained the age of 50 before such sale. Provides that in the case of a joint return, only one spouse need satisfy the age requirement.