American Airlines customers traveling from Atlantic City International Airport to Philadelphia International Airport using the Landline bus service can now check in, go through security at ACY and board the bus on the secure side of the airport. The Press of Atlantic City reports passengers using the service won’t have to go through security in Philadelphia, unlike previously when they did have to do that. The change is a result of the U.S. Transportation Security Administration’s recent approval of airside-to-airside transportation.