The airplane is a 777 freighter that will be delivered in February to Korean Air.
Boeing began the production increase back in October when the first parts of this 777 entered the factory.
The new rate should yield 100 777s annually.
"Our factory is running smoothly and we've reduced the time it takes to build a 777 by one day from 49 to 48 days," Scott Fancher, general manager of the 777 program, said in a statement.
New manufacturing innovations such as flex-track drilling in the body and wing panels, automated floor drilling and wings painting equipment also contributed.
Fancher also is vice president of the company's airplane development group, which will shape the updated 777X.
In less than three years, Boeing has increased 777 production from five jets monthly to 8.3, an all-time high for the program. The company has delivered 1,066 777s and has received orders for 1,431.
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