The FAA grounded the 737 Max models on March 13 after evidence emerged that a crash three days earlier of an Ethiopian Airlines flight that had just taken off from Addis Ababa had involved an erroneous activation of a device that repeatedly commanded the plane to dive.
Elwell said the return of the 737 MAX would be determined by what the FAA found in its analysis of Boeing's submission, adding that it was "pretty confident that the application is in good shape".
While sources told Reuters that the ungrounding is expected to happen in June, there's reportedly no firm timetable.
China Air Transport Association (CATA) has announced that it will support Chinese airlines to seek compensation for Boeing 737 Max suspension, May 24, 2019.
Safety regulators such as the European Union Aviation Safety Agency (EASA) and other aviation bodies are gearing up for their own vetting process of the 737 MAX before giving the green light for the resumption of flights.
Canada and Europe said Wednesday they would bring back the grounded aircraft on their own terms.
Earlier this week, China's biggest airlines formally asked USA planemaker Boeing to compensate them for losses caused by the grounding and delayed deliveries of 737 MAX jets.
According to previous plans, more than 130 such aircraft were scheduled to be delivered to Chinese airlines this year.
Shares of Boeing, the world's largest plane maker, pared earlier losses on Thursday to close down 0.6 per cent at $350.55 (Dh1285). The stock has fallen about 17 percent since the second crash, of an Ethiopian Airlines jet in March, wiping about 40 billion US dollars off its market value.
United Airlines said on Friday it is extending by one month its cancellations of Boeing Co 737 MAX flights, through August 3, as the jetliner remains grounded following two fatal crashes.
The agency hasn't given a timeline on when the 737 Max might be allowed to return to flight.
Elwell said that the process was still ongoing because the FAA had submitted further questions to Boeing about its technology fixes. Washington believes training on computers or tablets is sufficient for season pilots but Ottawa wants to require training on flight simulators.
"We should not, at this point, discount simulator training", Garneau told a press conference in Toronto.
Since the grounding, USA airlines have had to readjust schedules and come up with solutions in order to meet demand during the busy summer travel season.
In the meantime, United said it expects to cancel 35 to 40 flights a day in June and 40 to 45 flights per day in July.