Interestingly the article mentioned nothing about the gambling industry moving into Gulfport/Biloxi during the late 80's early 90's. I lived in New Orleans during the mid-80's and often drove to the beaches at Gulfport/Biloxi and remember once stopping at their regional airport and seeing their old brick terminal building (single floor and very small). Today they have a hugh terminal with 3-4 airlines (I think AirTrans still flies into Gulfport/Biloxi on subsity from the Casinos).
With reference to buses and buses from Philadelphia, I'd wonder if those are buses and buses a day or buses and buses a year. Fly 2 roundtrip RJ flights daily between Phildelphia and Gulfport/Biloxi, US Airways would likely want 70-80 daily O&D passengers. Mainline likely 170-190 daily O&D passengers.