The next generation of military aerospace systems will include advanced control systems whose size and complexity will challenge current verification and validation approaches. The recent adoption by the aerospace industry of model-based development tools such as Simulink® and SCADE SuiteTM is removing barriers to the use of formal methods for the verification of critical avionics software. Formal methods use mathematics to prove that software design models meet their requirements, and so can greatly increase confidence in the safety and correctness of software. Recent advances in formal analysis tools have made it practical to formally verify important properties of these models to ensure that design defects are identified and corrected early in the lifecycle. This paper describes how formal analysis tools can be inserted into a model-based development process to decrease costs and increase quality of critical avionics software.