The aerospace giant said this week that chief executive Dave Calhoun would leave by the end of the year.

He's departing amid a deepening crisis over safety and quality standards at the planemaker.

That follows January's midair blowout on a 737 MAX jet operated by Alaska Airlines.

Though no one was killed in the incident, it raised new doubts about how well the firm's best-selling aircraft is made.

The model had previously faced a long grounding over two fatal crashes traced to a design flaw.

Now investors want to know who the firm could choose to steer it out of crisis.

Chief Operating Officer Stephanie Pope had been seen as the heir apparent, but was this week named to run the firm's commercial airplanes division instead.

Analysts say that could be a sign Boeing wants to bring in an outsider to signal it is serious about change.

GE boss Larry Culp is one name being mentioned, after he led a sweeping overhaul at the conglomerate.

American Airlines chairman Greg Smith, who is also a former Boeing executive, is seen as another candidate.

Having worked at the planemaker and one of its big customers, he knows both sides of the industry.

Whoever is chosen, analysts say the firm seems to want a clean break with the past.

Unions say it's time to put an engineer in charge again.

That after widespread criticism that Boeing has put shareholder value ahead of product quality.