Canada and the United States grew increasingly isolated, Tuesday, by continuing to allow Boeing Max 8 operations as a crisis of confidence rattled the world’s air passengers.

The United Kingdom became the latest country to ban Max operations, in response to the crash of a 737 Max 8 aircraft in Ethiopia that killed 157 people, including 18 Canadians. It was the second Max 8 crash in less than five months, an almost unheard-of circumstance in modern aviation, where safety is the watchword.

“The UK Civil Aviation Authority has been closely monitoring the situation,” the UK Civil Aviation Authority said in a statement, “however, as we do not currently have sufficient information from the flight data recorder we have, as a precautionary measure, issued instructions to stop any commercial passenger flights from any operator arriving, departing or overflying UK airspace.”

Air Canada operates Max 8 flights from St. John’s and Halifax to London-Heathrow. If the ban were to be extended, Westjet flights would also be affected.

Soon after, Norwegian Airlines followed suit.

“In response to the temporary suspension of Being 737 Max operations by multiple aviation authorities we have taken the decision to not operate flights using this aircraft type, until advised otherwise by the relevant aviation authorities,” said Norwegian Chief Operating Officer Tomas Hesthammer. “We would like to apologize to customers for any inconvenienced caused, however, safety will always remain our top priority.”

Norwegian expects cancellations and delays as a result, but said in a statement, “the safety and security of our customers and colleagues will never be compromised, and once authorities advise to cease operations we will of course comply.”

In Canada, 41 Max 8s remain in operation. Twenty-four are operated by Air Canada, 13 by Westjet and four by Sunwing. Southwest and American Airlines are the largest Max operators in the United States, while United airlines operates the larger Max 9.

Transport Minister Marc Garneau said Canadian authorities are working closely with the U.S. Federal Aviation Administration and the National Transportation Safety Board, which both have investigators on the ground in Ethiopia.

The FAA announced Monday it was too early to recommend any actions as a result of the Ethiopian Airlines crash, but reiterated changes urgently recommended in the wake of a Lion Air Max 8 crash in October.

China was the first country to ban Max 8 operations and was later joined by Indonesia, Australia and Singapore, among others. Some airlines, including Aeromexico which flies to Canada, have grounded their own Max 8 operations, without waiting for regulators.