Donald Trump has suggested that modern planes are too complex in the wake of two deadly crashes in the past five months.
The US president said that the additional "complexity creates danger" and hinders pilots from making "split second decisions" to ensure their passengers' safety.
"Airplanes are becoming far too complex to fly. Pilots are no longer needed, but rather computer scientists from MIT. I see it all the time in many products. Always seeking to go one unnecessary step further, when often old and simpler is far better," Mr Trump wrote on Twitter.
He added: "Split second decisions are... needed, and the complexity creates danger. All of this for great cost yet very little gain. I don’t know about you, but I don’t want Albert Einstein to be my pilot. I want great flying professionals that are allowed to easily and quickly take control of a plane!"
The aircraft crashed in Indonesia last year and in Ethiopia on Sunday, killing all 157 people on board.
Airplanes are becoming far too complex to fly. Pilots are no longer needed, but rather computer scientists from MIT. I see it all the time in many products. Always seeking to go one unnecessary step further, when often old and simpler is far better. Split second decisions are....
— Donald J. Trump (@realDonaldTrump) March 12, 2019
At least nine Britons and one Irish citizen were among the dead, as were scientists, doctors, aid workers and three members of a Slovakian MP's family.
Mr Trump participated in a signing ceremony for a $15 billion (£11 billion) deal between US-based Boeing and the Vietnamese government during his trip to Hanoi for a summit with North Korean leader Kim Jong-un last month.
The lucrative deal includes Vietnam's Bamboo airways agreeing to purchase ten 787-9 Dreamliners worth about $3 billion, while airline VietJet’s order is for 100 737 Max planes valued at $12.7 billion, Boeing said.
The 737 series is one of Boeing's most popular planes but the Max 8 model has raised safety concerns for possibly hindering pilots' ability to overpower automated functions.
America's Federal Aviation Authority (FAA) said on Monday that it believes the Boeing 737 Max is airworthy.
Boeing has also said no new safety guidance is planned for the moment. “The investigation is in its early stages, but at this point, based on the information available, we do not have any basis to issue new guidance,” the company said in a statement.
However three senators have called for Mr Trump to take action as a precautionary measure.
Republican senator Mitt Romney said on Tuesday: "Out of an abundance of caution for the flying public, the @FAANews should ground the 737 MAX 8 until we investigate the causes of recent crashes and ensure the plane’s airworthiness."
Democrats Dianne Feinstein and Richard Blumenthal have also raised concerns.
The crash of Ethiopian Airlines Flight 302 was the 2nd devastating & alarming tragedy involving Boeing’s new 737 Max 8 planes in less than 5 months. These 2 catastrophic accidents—both claiming the lives of all on board—call into serious question the safety of these aircrafts.
— Richard Blumenthal (@SenBlumenthal) March 12, 2019
Boeing also announced late on Monday night that it has been developing a flight control software enhancement for the 737 MAX, developed in light of the Indonesian crash.
It will be put into effect in the coming weeks, to “make an already safe aircraft even safer”. It includes changes to “flight control law, pilot displays, operation manuals and crew training”.
The announcement came after the FAA said it would mandate “design changes” no later than April.