A Phd in aviation or flying has nothing to do with becoming a pilot....
Pilots have licenses just like a drivers license . Its not a college degree . Your educational qualification will always be high school ( unless you get a degree ofcourse )
One of the requirements in order to maintain a pilots license is to have a valid medical . Your pilots license will become invalid if you fail your medical .
If you fracture your hand or leg your medical will immediately become invalid and you wont be able to fly with immediate effect
However once you are healthy once again you can regain your medical and
continue to fly
PIA requires you to hold a CPL issued by the Civil Aviation Authority of Pakistan . They wont hire you with an American or European Pilot license
You will have to convert your license in order to apply .