An Ethiopian Airlines passenger jet bound for Nairobi crashed minutes after take-off on Sunday, killing 157 people on board. This raised a lot of questions about the safety of the Boeing 737 MAX 8 model. This was the same model of plane flown by Lion Air crashed off the coast of Indonesia in October, killing the 189 passengers on board.

Boeing released the new fuel-efficient MAX 8 in 2017 as an update to the older 737. The 737 is the passenger plane that is the economic juggernaut of the world’s largest. The plane’s only competition is the European Airbus SE’s A320neo family.

Boeing has delivered more than 370 MAX Airplanes to 47 customers, since its release. In the wake of Sunday’s crash, however, China ordered its airlines to ground the jet, a move followed by Indonesia and Ethiopia. Other airlines, from North America to the Middle East, kept flying the 737 MAX 8 on Monday after Boeing stated the plane was safe.

Southwest Airlines Co, which operates the largest fleet of 737 MAX 8s, still believes in the safety of all its Boeing planes even as it received a rush of inquiries from customers wanting to know if they were booked to fly on a 737 MAX 8.

There are still unanswered questions about the causes of the Lion Air crash, and officials and safety experts said it was too soon to draw links with the Ethiopian incident. Nonetheless, Boeing is in full support of the crash investigation and continues to provide technical assistance under the direction of the U.S. National Transportation Safety Board and Ethiopian authorities.