Boeing is scrambling to restore confidence in the 737 Max from regulators, customers and the flying public. The manufacturer's 737 Max has been grounded across the globe since mid-March after a deadly crash involving the jet in Ethiopia. Less than five months earlier, a Boeing Max crashed in Indonesia.
The disasters killed a total of 346 people. Investigators said the jet's MCAS flight control system, which is designed to push the aircraft's nose down to prevent stalling, was involved in the crashes.
"This is a different show for us, it is not about orders. It is really focused on safety and the safe return of the Max flight," Muilenburg told CNBC's Phil LeBeau at the Paris Airshow on Monday.
"We are making good, steady progress on the certification work," Muilenburg said, before adding the company was hoping to schedule the certification flight "very soon."
The Wall Street Journal reported Sunday that Boeing could start flight testing the Max as early as this week, citing unnamed sources familiar with the matter.
Responding to this report on Monday, Muilenberg told CNBC the certification flight would take place in the "near-term" but he refused to provide a more specific timeline.
"It is important for us to focus on safety, we will get back up in the air when it is safe, that's the most important thing here."
"We are very confident in the MAX family and the heart of the market where it is located," Muilenburg said.
Boeing's chief executive said he was not focused on orders for the 737 Max during his time in the French capital, insisting there would be "plenty of opportunities" in the coming months. Muilenburg said the company had more than 4,000 of the 737 Max aircraft in backlog.
Boeing has previously said it has completed software changes for the jets, but the Federal Aviation Administration and other international flight agencies have yet to approve the updates.
Earlier this month, Muilenburg said that he expects the planes will get a green light to fly again by the end of the year. He declined to provide a more specific timeline when asked on Monday.
Airlines that have purchased the 737 Max, including American Airlines, United Airlines and Southwest Airlines have canceled thousands of flights due to the grounding and have scrambled to meet demand during the peak summer travel season.
Surveys have shown some passengers would avoid flying on the 737 Max, even after aviation safety officials allow it to return to service. Boeing's CEO has admitted the company will have to repair "damaged trust" of the flying public over the coming months.