Gov. Gary Locke, surrounded by legislators, business and civic leaders and aerospace union officials, signed a hefty package of tax breaks for the state’s entire aerospace industry — contingent on Boeing building its new 7E7 “Dreamliner” jet here.

The tax package, rushed through the Legislature last week as a last-minute sweetener to the state’s bid, is a key feature of the state’s sales pitch to keep Boeing assembly work here, the governor said.

The state is putting finishing touches on a multimedia bid proposal that will go to Boeing officials and site-selection consultants in Seattle, Chicago and South Carolina on Friday.

State trade Director Martha Choe and Locke said they’re optimistic that Washington will be selected — either Everett, where the company already assembles jets in the world’s largest manufacturing facility, or Moses Lake in Eastern Washington, where the company owns land at a former Air Force base.

The package includes a 40 percent cut in business taxes, sales taxes, research and development tax credits and lower property taxes. Washington has no corporate or individual income tax.

The phased-in breaks are worth about $400 million over the next six years and potentially an estimated $3.2 billion over 20 years.

Boeing officials were not present for the ceremony today and haven’t directly commented on the tax package.