These B17 and B24 Bombers have visited the Livermore Airport on Memorial Day for the past ~10 years.
For a modest fee you can climb through both planes.
for about $450 you can take a 30 minute ride in one of the planes.

For More info: The Collings Foundation.

2016:  The planes will be here from May 29-31.  Click here for details.

See also the eLivermore.com Airport Appreciation Day photos.

B17 Flying Fortress

B24 Liberator.  This is the only one left which flies.

The B24 flying over the Livermore Airport

B24 Landing

B17 Cockpit

B17 Bombs

Inside the B24