The museum announced it will reduce admission costs by 40 percent and offer cupcakes to the first 500 visitors. The museum's exhibit gallery is open from 10 a.m. to 7 p.m.
The facility opened in 1973 and was named after a prominent San Diego aircraft manufacturer. It offered the first IMAX dome theater in the world, which is now the only one of its kind in Southern California.
The celebration is in conjunction with the opening of a new IMAX film, "Rocky Mountain Express."
The museum is scheduled to hold a 40th anniversary gala on May 11.