The Federal Aviation Administration on Wednesday cleared Boeing's 737 MAX to fly again in the U.S. — 20 months after the plane’s worldwide grounding.

Why it matters: A pair of fatal planecrashes laid bare the gross oversight and safety lapses on the part of Boeing and the FAA. The fallout led to the resignation of top executives — including Boeing's CEO — a criminal investigation, and the company’s biggest financial hit in its century-long history.

The state of play: The planes likely won’t be in the air for several more weeks, if not months. Airlines will need to update the flight software, and pilots will need training.

• International aviation regulators are expected to follow the FAA’s lead and lift bans on the MAX.

Catch up quick: In both MAX crashes — which killed 346 people — pilots lost control of the MAX when a sensor in its flight control system malfunctioned and relentlessly pushed the nose of the plane downward.

• There was no backup sensor. Pilots weren’t adequately trained on the flight control system and couldn’t counteract quickly enough.
• Boeing has made software changes — including ones that limit the system’s capability to push the plane's nose down. The FAA conducted a series of certification test flights of the MAX.

The big picture: Orders of the company’s best-seller were expected to rebound after the ungrounding. That was before the pandemic hit — and before fears about contracting the virus led to a collapse in travel.

• The unprecedented travel slump means airlines don’t need more MAX jets — or any other new planes.
• Boeing is closer now to offloading its 450 MAX jets sitting in storage, though some airlines have pushed off deliveries of previously ordered planes or canceled them altogether.

The bottom line: Even when consumers do feel safe to fly again, the MAX will have to overcome the reputational damage from the crashes.