Two planes are out of service after a collision knocked the "S" out of Southwest on one of the aircraft.<br />On Saturday, two Southwest planes were pushing back from the gate at Nashville International Airport.<br />According to CNN, one was headed to St. Louis and the other to Atlanta.<br />They backed into each other, with one clipping the winglet of the other.<br />No injuries were reported, and the planes were able to return to the gates on their own.<br />The aircraft were taken out of service to be evaluated. <br />
