An unusual war of words erupted into plain view Tuesday, with some of the world’s most important aviation regulators disagreeing publicly on the safety of Boeing’s Max aircraft.

The spat followed the crash of an Ethiopian Airlines 737 Max 8 plane on Sunday that killed 157 people, including 18 Canadians. It was the second fatal crash involving the type in less than five months, an unheard-of tally for such a modern aircraft.

Numerous regulators decided Tuesday to ban the 737 Max airplane from their airspace, leaving North America increasingly isolated in allowing Max operations to continue.

By Tuesday afternoon, the Federal Aviation Administration was striking back.

“The FAA continues to review extensively all available data and aggregate safety performance from operators and pilots of the Boeing 737 MAX,” wrote the agency’s acting head Daniel K. Elwell. “Thus far, our review shows no systemic performance issue and provides no basis for ordering grounding the aircraft. Nor have civil aviation authorities provided data to us that would warrant action.”

UPDATED #FAA Statement regarding @Boeing 737 MAX. pic.twitter.com/HxObBr7qRf

— The FAA (@FAANews) March 12, 2019

The European Union Aviation Safety Administration became the latest jurisdiction to ban the aircraft Tuesday, subtly questioning the Boeing Max’s safety record. It joined numerous agencies and airlines around the world to ground the Max.

“Following the tragic accident of Ethiopian Airlines flight ET302 involving a Boeing 737 MAX 8, the European Union Aviation Safety Agency (EASA) is taking every step necessary to ensure the safety of passengers,” the agency said in a statement ordering the grounding of the continent’s Max fleet.

Air Canada flights from Halifax and St. John’s to London-Heathrow were cancelled as a result. Passengers were being rebooked on flights through Toronto, Ottawa and Montreal.

Canadian regulators were closely following developments, but apparently leaving the heavy lifting to the FAA and the National Transportation Safety Board. Transport Minister Marc Garneau cancelled meetings to speak with aviation advisors, but declined to take action, urging Canadians not to jump to conclusions.

The Max is currently the best-selling aircraft in Canada. Air Canada operates a fleet of 24 Boeing 737 Max 8 aircraft, Westjet 13, and Sunwing four with more aircraft on the way.

Boeing also issued a statement defending the safety of its newest, and fastest-selling, aircraft.

“We have full confidence in the safety of the 737 MAX,” the company said in a post on Twitter.

Boeing Statement on 737 MAX Operation: https://t.co/mrzADVRMKZ pic.twitter.com/L8eF4r0pTl

— Boeing Airplanes (@BoeingAirplanes) March 12, 2019

Westjet continued to stand by the plane’s safety, Tuesday.

“WestJet remains actively involved in discussions with Transport Canada, Boeing and fellow Canadian operators of the Boeing MAX 737 aircraft,” spokesperson Lauren Stewart told Western Aviation News in an e-mail, “and reassures our guests and employees that we will continue to fly with their safety and best interests at the forefront.”