No more than it is to fly at the university. The only problem is financing - most student loans don't cover flight training outside of the university.
However, I will offer this advice: please, PLEASE don't major in aviation! You never know when things may go wrong. I majored in flight, got through my private, started on my instrument and ran into medical issues. I'm graduating with a degree in Aviation Science & Admin from WMU and I can't buy a job.
There will always be pilot jobs out there, and they don't give a crap what you majored in. Choose a major that interests you in a field that can get you a job should you lose your medical, or something else keeps you out of the air. If you absolutely love airplanes, I would suggest aeronautical engineering. However, any degree will do. Even dance is more useful than aviation science.