What might it mean to have hyperinflated lungs on chest xray, but following spirometry tests are perfect?

May mean nothing: Hyperinflated lungs may mean a lot of air in the lungs, which depends on whether the person was breathing in or out at the time of x-rays. It may mean bronchial asthma, and or emphysema. If you do not smoke cigarettes and do not have bronchial asthma, it means nothing. At times tall slender man may have large and long lungs which may look like hyperinflated lungs on chest radiographs.

Emphysema: Early emphysema may show normal pulmonary function test. Spirometers, lung conditions are challenging to define even for doctors. See your doctor or pulmonologist.