Donald Trump grounded Boeing’s 737 Max fleet on Wednesday, days after the second fatal crash involving the plane in five months.

Issuing an emergency order, Trump said all 737 Max jets in the US would now be grounded. “Planes that are in the air will be grounded if they are the 737 Max. Will be grounded upon landing at their destination,” Trump told reporters at the White House.

Trump said the safety of the American people and others was of “paramount concern”. He said: “They [Boeing] have to find the problem … and they will find it.”

Ethiopian Airlines said on Thursday an Ethiopian delegation had sent the black boxes from the crashed plane to Paris for investigation.

Boeing said it had “full confidence in the safety of the 737 Max” but “out of an abundance of caution and in order to reassure the flying public” it had decided to temporarily suspend the entire fleet.

But a statement from the Federal Aviation Administration (FAA) went further, saying that new information from the wreckage of a 737 crash in Ethiopia had uncovered similarities to an earlier crash of the same variant of 737 in Indonesia in October.

The FAA’s emergency order states that the similarities “warrant further investigation of the possibility of a shared cause for the two incidents that needs to be better understood and addressed”.

The United States had stood virtually alone in allowing the plane to keep flying. On Wednesday, Canada joined a growing list of countries that had grounded the aircraft involved in the Ethiopian Airlines crash that killed 157 people this week.

Boeing and US aviation safety officials at the FAA had resisted mounting pressure from Congress and labor unions to halt operation of the Boeing 737 Max while investigators work to find the cause of the crash. Regulators in the European Union, the United Kingdom, China, Australia and India have restricted the planes from flying. The latest bans came from Egypt, Thailand and Vietnam on Wednesday.

The grounding threatened chaos for US travelers. Dozens of the planes were still airborne at the time of the announcement and future flights will have to be rescheduled until the ban is lifted.

At New York’s LaGuardia airport, three flights to Miami on 737 Max 8s were cancelled, stranding hundreds of American Airlines passengers.

“I’d rather the inconvenience than be on a dangerous airplane,” said Marie Bellamota, a traveller from the Dominican Republic who had her flight cancelled. “I feel upset, and I have to change all my plans but what can I do?”

Other passengers said they were inconvenienced but relieved to not be taking the risk or suffering the anxiety of taking the troubled Boeing.

“I’m glad. I didn’t want to be on that plane anyway,” said Sharon Gentles, who was on her way to Jamaica for a funeral. “I’m happy they grounded them because at least I’m safe.”

A spokesman for American at LaGuardia said that over the past several days the airline had sought to allay customers’ increasing concerns about the 737 by switching them to other flights without imposing additional fees.

Following the planes’ grounding by US regulators, the airline switched passengers to a “special section” plane – a wide-bodied Boeing 777 leaving JFK at 10.30pm. “We’re happy to provide at least some relief by getting them to their destination tonight,” said American’s Justin Franco.

The Ethiopian crash comes just five months after the deadly crash of a new Boeing 737 Max 8 operated by Lion Air in Indonesia, which left 189 people dead. No evidence has yet linked the crashes, but pilots on both planes reported problems moments after takeoff and asked to make emergency landings.

Canada’s transportation minister, Marc Garneau, said the decision to issue a “safety notice” was based on a review of newly available satellite tracking data, which identified similarities between the crash in Ethiopia and the one last year in Indonesia.

Garneau cautioned that the information was “not conclusive” but that “at this point we feel that threshold has been crossed”.

On Tuesday, Boeing’s CEO, Dennis Muilenburg reportedly spoke with Trump by phone to assure him the planes were safe. The call came after the president complained on Twitter that airplanes have become “far too complex to fly” and suggested that “pilots are no longer needed, but rather computer scientists from MIT”.

But Trump and Boeing had faced mounting pressure to act. Senator Ted Cruz, a Texas Republican who leads a Senate subcommittee overseeing aviation, called on the FAA to ground the planes and promised to hold hearings on the cause of the crash.

“Further investigation may reveal that mechanical issues were not the cause, but until that time, our first priority must be the safety of the flying public,” he said on Tuesday.

My flight back to Orlando was the Boeing 737 so now I can’t go back LMAO wish me luck finding a flight pals — Amber Nicole (@ambernxoxo) March 13, 2019

Senator Dianne Feinstein, a California Democrat, and the Massachusetts senator Elizabeth Warren, a Democratic presidential candidate, had called for the planes to be grounded. Warren said lawmakers should hold hearings “on whether an administration that famously refused to stand up to Saudi Arabia to protect Boeing arms sales has once again put lives at risk for the same reason”.

Boeing, one of the US’s largest manufactures, is a lobbying powerhouse with deep ties to the White House and Congress. According to OpenSecrets.org, a group that tracks lobbying data, Boeing spent more than $15m on Washington lobbying last year.

Trump’s acting defense secretary, Patrick Shanahan, worked at the company for more than 30 years. On Wednesday, the Citizens for Responsibility and Ethics in Washington filed a complaint with the Department of Defense’s Office of Inspector General alleging that Shanahan violated ethics rules “by promoting Boeing in the scope of his official duties” at the DOD.

The US airline carriers that fly the plane – Southwest, American Airlines and United – on Wednesday said they were complying with the new requirements.

In a statement, Southwest said the airline removed all of its 34 Max 8 aircraft from scheduled service. American, responding to customer questions on Twitter, said it had stopped operating all 24 of its planes of that type and United grounded its 14 737 Max 9 aircraft, which handle about 40 flights a day.