Fatal Boeing planes that were responsible for two horrific crashes could return to the skies by July or August.

The 737 MAX was grounded following an Ethiopian Airlines crash that killed all 157 on board just five months after a similar Lion Air accident that claimed all 189 people.

The ABC reports Boeing has told one of its biggest buyers, Indian budget airline SpiceJet, that the aircraft should be returning to the skies by July.

However the International Air Transport Association (IATA) expects it could take until August before the planes returns to service but the final timing rests with regulators.

“We do not expect something before 10 to 12 weeks in re-entry into service,” IATA director general Alexandre de Juniac said.

“But it is not our hands. That is in the hands of regulators.”

Earlier in May Boeing announced it had completed a software update and associated pilot training to prevent erroneous data from triggering a system called MCAS, which was activated in both the planes before they crashed.

Debris from the Ethiopian Airlines tragedy in March which sparked the global grounding of Boeing 737 planes. Photo: Getty

IATA plans to organise a summit with airlines, regulators and the manufacturer in four to seven weeks to discuss what is needed for the 737 MAX to return to service, Mr de Juniac said.

At an IATA meeting in Montreal last week, airline members said they wanted regulators to cooperate closely on the decision for the plane’s re-entry to service.

“We hope that they will align their timeframe,” Mr de Juniac said of regulators.

America’s Federal Aviation Administration (FAA) expects to approve the jet’s return to service as soon as late June, representatives of the US air regulator informed members of the United Nations’ aviation agency in a private briefing last week, sources told Reuters.

US operators United Airlines, Southwest Airlines, and American Airlines have removed the planes from their flight schedules until early to mid August.