Southwest is actually eliminating the Philadelphia to Columbus route:
http://www.philly.com/philly/business/50698977.html

"Southwest Airlines Co. will discontinue nonstop service from Philadelphia to Columbus, Ohio, and San Antonio, Texas, on Nov. 1."

US Airways was price-matching the $49/one way trips, and given the two if US Airways price matches, I'm asuming ppl would rather take US Airways to accumulate FF miles, or US Airways was willing to keep losing money on this route longer when both were competing.

However, this will eliminates the cheap airfares altogether now from Philly/NJ into OH as US Airways will likely raise prices big time. And, I'm sure there were those in North Jersey who would drive to Philly to fly to Columbus to rent a car and reach Cleveland, or vice versa.

The PHL to PIT route still remains however, and PIT is within 2 hours drive of Columbus or Cleveland. Cincinnati and Dayton would be a problem. Columbus being the most centralized, it had value being 2 hours drive to most of OH. Cincinnati, Columbus, and Cleveland are the largest 3 OH metros.

One can still drive or take the train to Baltimore/BWI. But the PHL flight with routing of MDW or BNA is way too long. One can likely drive to OH in almost the same time.