Shared with you
In interviews, the real Jim Lovell had said that he thought Kevin Costner looked a little bit like him, but Costner was never cast. When Brian Grazer and Imagine Entertainment got the rights to the script, Ron Howard signed on to direct, and knowing that Tom Hanks was an Apollo/space buff, Ron sent the script to him. They set up a meeting, and Hanks agreed to play Jim Lovell during that meeting.
In a commentary track, Marilyn Lovell comments that Tom Hanks exactly portrays Jim Lovell's mannerisms and style of movement.
Bill Paxton, Tom Hanks and Kevin Bacon were all very proud of the fact that they weren't sick on the so-called Vomit Comet - the plane used to simulate zero gravity. The cameramen weren't so lucky.
In some scenes where the Earth can be seen from the windows of Apollo 13, it is one of the photos taken by Jim Lovell and Bill Anders on the Apollo 8 mission.
Jim Lovell wore his old Navy Captain's uniform in the scene where he greets the astronauts aboard the U.S.S. Iwo Jima. When Ron Howard asked Lovell if he'd like to be in the film as the ship's Admiral, Lovell agreed, but pointed out, "I retired as a Captain; a Captain I will be."