From the Chicago Tribune (cut & paste of the link by OP):

CHICAGO - An American Eagle truck backed into an American Airlines plane Monday morning as the aircraft was leaving its gate at O'Hare International Airport, officials said.

No one was injured, and the incident was under investigation.

The accident happened around 10:30 a.m. as Flight 403 was getting ready to depart for El Paso, Texas, American Airlines spokesman Billy Sanez said.

The MD-80 had 111 passengers and five crew members on board.

All were transferred to another plane that departed two hours later.

>>>>Strange that the OP mentions a second occurrence - I wonder if the Trib got the timing wrong...