To flight qualify is to take a product, process, or material and test it in order to prove that it will withstand the environment of aerodynamic or space flight. This process can include the following tests and processes:

• parts screening
• thermal test
  Infrared and thermal testing
  Infrared and thermal testing is one of many Nondestructive testing techniques designated by the American Society for Nondestructive Testing . Infrared Thermography is the science of measuring and mapping surface temperatures....
  
  
• vacuum test
  Vacuum chamber
  A vacuum chamber is a rigid enclosure from which air and other gases are removed by a vacuum pump. The resulting low pressure, commonly referred to as a vacuum, allows researchers to conduct physical experiments or to test mechanical devices which must operate in outer space...
  
  
• vibration test / Modal testing
  Modal testing
  Modal testing is a form of vibration testing of an object whereby the natural frequencies, modal masses, modal damping ratios and mode shapes of the object under test are determined.A modal test consists of an acquisition phase and an analysis phase...
  
  
• material analysis

A flight qualification can actually include a test in the actual desired environment.