Boeing workers in Everett have begun assembly of the first aerial refueling tanker under the big Air Force contract to supply 179 planes.

The aircraft, based on Boeing’s 767, is due for delivery in 2016. Boeing said assembly work began with an 82-foot wing spar, and the production line is being readied to build the tanker’s aft and forward body structures.

The aircraft will be assembled in November and will roll out of the factory in January, the company said.