Boeing has rolled out the first Next-Generation 737 built at the new production rate of 38 airplanes a month. Panamanian customer Copa Airlines will take delivery of the 737-800 in early April.

The airplane will now undergo functional, systems and flight testing over the next three weeks before being delivered.

Boeing is in the process of increasing the production rate on its 737 program from 35 to 38 airplanes per month because of market demand for the world’s best-selling commercial jetliner. Next year, the 737 production rate will increase to 42 airplanes per month.

Copa Airlines operates a fleet of more than 50 Next-Generation 737s.