The FAA said its order was prompted by new evidence from the Ethiopian Airlines crash site gathered on Wednesday which, together with newly-refined satellite data of the aircraft's flight path, indicated similarities with the Lion Air flight which killed all 189 people on board on Oct 29 a year ago.
The Boeing Max 8 jet is now at the center of a growing global ban after more than 40 countries grounded the model following the second fatal crash in five months.
A USA official said the FAA was aware of the satellite data Mr Garneau had cited but called it inconclusive.
He said that satellite data showed possible similarities between flight patterns of Boeing 737 Max planes operating in Canada and the Ethiopian Airlines plane that crashed.
"It became clear to all parties that the track of the Ethiopian Airlines [flight] was very close and behaved very similarly to the Lion Air flight", FAA acting administrator Dan Elwell said.
American Airlines issued a statement Wednesday saying: "Our team will work with all customers impacted by these flight cancellations in order to rebook them to their final destination".
Tucker Carlson Defended Statutory Rape As Recently As 2015
Some made a decision to contact Carlson's advertisers to chide them for advertising during the host's week night program. Do you believe what he has said in the past is relevant for today? The audio from Media Matters swiftly went viral.
Passengers said the flight was smooth, but some said it wasn't enough to ease their worries. "As a result, we have removed our 34 MAX 8 aircraft from scheduled service".
"Trump said any plane now in the air will go to its destination and then be grounded, adding that pilots and airlines have been notified".
After China grounded the plane on Monday, several countries followed suit, including much of Europe.
Tim Ghriskey, chief investment strategist at Inverness Counsel in NY, said the grounding gives Boeing time to address any problems and not face another potential disaster. Most airlines have spare planes positioned throughout the country to deal with mechanical and weather delays, he said.
Analysts say North America will face the most disruption as Southwest Airlines, Air Canada and American Airlines are the three largest operators of the 737 Max aircraft in the world.
Around 75 737 MAX flights are operated daily, representing less than six per cent of Air Canada's approximately 1,600 daily flights.
With the uncertainty hanging over the 737 Max, a French presidential source said European planemaker Airbus and Ethiopian Airlines are discussing a possible new contract as part of the airline's fleet overhaul. All 189 people on board Lion Air flight JT610 were killed. The stall warning tried to put the plane in a nose dive and unlike a previous incident when the pilots were able to shut off the motor pushing the nose down, the pilots on the Lion Air flight that crashed didn't take that step.
An Australia-based frequent flyer, who asked not to be named, told Business Traveller Asia-Pacific that when he was taking a Garuda flight in Indonesia on Tuesday, "everyone was checking it wasn't a Max".