Boeing has completed a software update for its 737 Max jets, which have been grounded worldwide since March after they were involved in two fatal crashes.
The planemaker said it was in the process of submitting a pilot training plan to the US Federal Aviation Administration and would work with the regulator to schedule its certification test flight.
The FAA is planning a meeting on 23 May in Fort Worth, Texas, with regulators from around the world to update them on reviews of Boeing’s software fix and on pilot training.
Aviation regulators from other countries will have to assess Boeing’s proposed fixes and clear the aircraft to fly in regions independently of the FAA.
It is unclear when the 737 Max aircraft will return to service but US airlines have said they hope the jets will fly this summer.
Southwest Airlines and American Airlines, the two largest US operators of the Max, pulled the planes from their schedules until 5 August and 19 August respectively.
The airlines, which must still decide on pilot training, have said they would use the jets as spare planes if they are approved for flight before those dates.
The FAA said on Thursday that Boeing had not yet submitted its final software package for approval.
The 737 Max was grounded after an Ethiopian Airlines crash in March killed all 157 on board. It happened five months after a similar crash of a Lion Air flight killed 189 people.
Boeing said it hoped the software upgrade and associated pilot training would add layers of protection to prevent erroneous data triggering a system called MCAS, which was activated in both the planes before they crashed.
It said it had completed simulator testing and engineering test flights as well as developed training and education materials, which were being reviewed by the FAA, global regulators and airline customers.
To date, Boeing had flown the 737 Max with the updated software for more than 360 hours on 207 flights, the company said.