Boeing Co.’s best-selling plane is under a cloud. Regulators and airlines around the world are suspending operation of the Boeing 737 Max as they await answers on what caused the fatal March 10 crash of an Ethiopian Airlines flight, less than five months after the same type of plane flown by Lion Air plunged into waters off Indonesia. The plane continues to fly in the U.S., where the Federal Aviation Administration, often viewed as a global authority on air safety, said it sees “no basis to order grounding the aircraft.” Travelers elsewhere may be wondering whether the global action will