In February last year, a new Southwest Airlines Boeing 737 Max plane was on one of its first flights when an automated stabilizing system appeared to malfunction, forcing the pilots to make an emergency landing soon after they took off.

Less than two months later, an Alaska Airlines 737 Max plane with eight hours of total flight time was briefly grounded until mechanics resolved a problem with a fire detection system. And in November, an engine on a just-delivered United Airlines 737 Max failed at 37,000 feet.

These incidents, which the airlines disclosed to the Federal Aviation Administration, were not widely reported. There were no indications that anyone was in danger, and it was not clear who was ultimately responsible for those problems. But since Jan. 5, when a panel on a two-month-old Alaska Airlines 737 Max 9 jet blew off in midair, episodes like these have taken on new resonance, raising further questions about the quality of the planes Boeing is producing.

“There’s a lot of areas where things don’t seem to be put together right in the first place,” said Joe Jacobsen, an engineer and aviation safety expert who spent more than a decade at Boeing and more than 25 years at the F.A.A.

“The theme is shortcuts everywhere — not doing the job right,” he added.