Shares of the company at last check were down nearly 1% to $237.13. They have been up almost 11% year to date.
The MAX 10, a slightly larger version of MAX jets that are already flying, took off near Seattle, the Associated Press reported.
A Boeing spokesman said the company plans to issue a news release about the flight later Friday.
The company expects to begin delivering MAX 10s to airlines in 2023.
The MAX 10 has been a slow seller compared with the Airbus A321 family, attracting 550 orders from 20 customers, according to The Wall Street Journal.
MAX jets get better fuel mileage than previous versions of Boeing’s venerable 737.
Airlines began using the plane in 2017, but MAX 8 and MAX 9 planes were grounded worldwide for nearly two years after crashes in October 2018 and March 2019 killed a total of 346 people.
The Federal Aviation Administration approved resumption of flights in November 2020. Boeing made changes to the aircraft, including overhauling flight-control software that played a role in the crashes.
The software function operates only in unusual flight conditions and now relies on two sensors, activates only once and never overrides pilots’ ability to control the airplanes.
Boeing said it May that it had received approval the FAA for a fix to an electrical grounding issue that had affected about 100 737 MAX airplanes.
In April, Boeing posted its sixth consecutive quarterly loss as it warned that the COVID pandemic continues to challenge the global aircraft market.
The plane maker also said an electrical fault in certain 737 MAX jets had paused deliveries of the workhorse aircraft.