For airline customers of Boeing’s 737 Max there is no quick way out of the crisis of confidence that threatens to engulf the aircraft in the wake of the Ethiopian Airlines crash nine days ago that killed all 157 people on board.

Most of those that have 737 Max 8 aircraft on order, including Norwegian Air and Icelandair, have so far said they will maintain them pending the outcome of the investigation.

Yesterday, Canada’s budget operator WestJet Airlines became the second carrier to warn its financial performance would be hit by the global grounding of the 737 Max fleet. The warning comes after Canada’s largest carrier, Air Canada, last Friday issued a similar warning. The airline normally operates 24 Boeing 737 Max aircraft out of its fleet of 392.