Chris Carlson, Associated Press
Members of Barack Obama's entourage unload at Midway airport in Chicago Saturday after a mechanical problem forced a change of charter airplanes on short notice. The public announcement system on Obama's leased 757 jet malfunctioned Saturday, when the plane landed without incident in Terre Haute, Ind., for a campaign event.

Members of Barack Obama's entourage unload at Midway airport in Chicago Saturday after a mechanical problem forced a change of charter airplanes on short notice. The public announcement system on Obama's leased 757 jet malfunctioned Saturday, when the plane landed without incident in Terre Haute, Ind., for a campaign event.