Norwegian has offered low-cost flights between Cork, Dublin, and Shannon in Ireland, and airports in Canada and the US since 2017.
The FAA hopes civil aviation authorities around the world will decide at about the same time to allow the Boeing 737 Max to resume flying.
Boeing said that if the plane is grounded past the targeted Q4 timeline, the planemaker may be forced to suspend production, impacting 12,000 workers.
The pilots accuse Boeing of putting profit before safety, and say the continued grounding of the 737 Max has made their careers less certain.
The President and CEO of Boeing Global Services told the Paris Air Show that Boeing is applying what it learned from the 737 Max to the 777x.
Norwegian tried to move a 737 Max plane from Málaga, Spain to Stockholm, Sweden, so it can keep its fleet together as it awaits a software update.
The public may not trust the Boeing 737 Max planes, even after the US Federal Aviation Administration (FAA) approves their software upgrade.
Wall Street is still overwhelmingly positive about Boeing's prospects, despite the company losing more than $50 billion of value after two crashes.
Boeing made changes to the automated software without alerting engineers, pilots, and regulators, according to a New York Times report.
"Unfortunately, I can't change what happened," Boeing's CEO said in an interview with CBS. "I would if I could."
The exchange centered on the 737 Max's angle of attack (AOA) indicator, a feature only available as a paid-for extra.
US aviation authorities consider bird strikes to be the most likely reason why an AOA sensor on the Ethiopian Airlines jet failed.
All 371 Boeing 737 Max airliners have been grounded since March 13 after the crashes of Lion Air Flight JT610 and Ethiopian Airlines Flight ET302.
"We shouldn't have to be here today," Rep. Peter DeFazio told FAA acting administrator Daniel Elwell at a House hearing
American Air CEO: "I know for certain that if (737 Max) is certified and an American Airlines pilot is comfortable flying it, then it's 100% safe."
The Verge reported that Boeing deployed account representatives to convince airlines to remain confident in the new jet after the October 2018 crash.
Boeing CEO Dennis Muilenburg explained on Monday why it didn't notify 737 Max pilots of the existence of MCAS.
A proposal that would have separated the CEO and board chairman roles at Boeing did not pass at the aerospace manufacturer's shareholder meeting.
Southwest, American Airlines, Tui, and Norwegian have all warned of hits to their profits after the Boeing 737 Max was grounded.
Experts agree that modern airliners such as the Boeing 737 Max and Airbus A320neo are designed to compensate for deteriorating pilot skills.