After the war, Boeing designed its first commercial airplane with the vast water areas of the Northwest in mind. The B-1 was a conventional pusher flying boat that could carry a pilot and two passengers as well as mail or cargo. The hull was laminated wood verneer, and the wing frames were spruce and plywood. Although a good airplane, the B-1 did not sell well because the market was overwhelmed with cheap war-surplus aircraft.

The only B-1 built was sold to Eddie Hubbard, who was awarded one of the first airmail contracts. Flying more than 350,000 miles over a span of 8 years, the B-1 wore out six engines shuttling mail between Victoria, British Columbia and Seattle.