Two months after Ethiopian Airlines Flight 302 crashed, killing all 157 people on board, the CEO of the airline said his crews and passengers have lost confidence in the Boeing 737-MAX and he wants the company to conduct a more thorough review of the plane.

In an exclusive interview with NBC News on Monday, Tewolde Gebremariam said that the airline doesn't yet know if it will fly the Boeing 737-MAX planes again. But he said, "At this stage I cannot, I cannot fully say that the airplane will fly back on Ethiopian Airlines. It may, if we are fully convinced and if we are able to convince our pilots, if we are ever to convince our traveling public."

However, he also said that if the planes were back in service, Ethiopian Airlines would be "the last airline to fly them again." "We have not got a time to discuss on the return to service and we have made it very clear on several occasions we would not be the first one to return their airplane back to air."

Gebremariam said it's not enough for Boeing to only review the "MCAS" anti-stall system believed responsible for the fatal crashes in Indonesia and Ethiopia. He wants a much more rigorous review of the plane.

"We strongly believe that entire flight control system needs to be reviewed," he said.

The Ethiopian Airlines crash on March 10 followed a Lion Air crash in Indonesia last October. The two crashes were responsible for 346 deaths.

Investigators in both countries say the Boeing 737-MAX's new MCAS anti-stall system seems to have played a role.

"It's very abnormal for a new airplane to have two accidents, fatal accidents in a span of five months," he said. "These are brand new airplanes."

Boeing has admitted that "MCAS" misfired, putting both the Indonesian and Ethiopian planes into a fatal nose dive. The company is expected to submit its software fix for Federal Aviation Administration approval later this month.

But investigators have also noted the Ethiopian pilots were flying much faster than is typical, more than 500 miles per hour.

Still, Gebremariam insisted the pilots did everything they could to save their plane.

"They have followed the procedures correctly," he said. "This should not happen again to any airline, even a single life should not be put at risk."

Boeing said in a statement, "Boeing is working closely with pilots, airlines and global regulators to update the max and help prevent this tragic loss of life from happening again.”

Gebremariam said the airline's relationship with Boeing goes back more than 60 years, and he has confidence in Boeing, even if his crews have lost confidence in the 737-MAX.

"We still have very strong confidence in Boeing, but we want them to do the right thing without rushing to make sure this airplane is safe and clear confidence in all of us before it returns back to air."