Defense Flexibility Act - Authorizes the Secretary of Defense to transfer amounts appropriated to the Department of Defense (DOD) in any of FY2014-FY2021 that are subject to reduction under a sequestration order issued pursuant to the Balanced Budget and Emergency Deficit Control Act of 1985 between such appropriations to address an urgent national priority or the consequences of a national emergency resulting from such sequestration.

Limits the amount transferred to an appropriation under this Act to the amount by which such appropriation is reduced under the sequestration order. Prohibits obligation of transferred amounts unless the Secretary notifies the House and Senate Armed Services Committees at least 30 days in advance of such transfer.