[On Wednesday, Canada was the latest country to ban Boeing 737 Max planes from its airspace. Read the latest about the bans here, or read more updates on the Ethiopian Airlines crash here.]

As he waited on Tuesday morning to board Southwest Flight 2315 from Oakland to Los Angeles, William Gonzales learned that the plane that he was about to board was a Boeing 737 Max 8.

“This is the Max?” Mr. Gonzales asked, his eyes widening. “I’m not getting on that plane if it’s the Max.”

The model, which on Sunday was involved in a fatal crash for the second time in five months, had by Tuesday been banned from the national airspace of China, Australia and countries in the European Union. At least 34 airlines around the world have grounded their planes since Ethiopian Airlines Flight 302 crashed on its way from Ethiopia to Kenya, killing all 157 people on board.