Planes can be switched out last-minute. I plan to check the plane type at the gate every time I fly for the next 10 years, and if it's a MAX, I'll reschedule my flight on the spot.
They claim they solved the software problem, but they didn't solve the physics problems created by the engine position (which necessitated the software in the first place).
They claim they solved the software problem, but they didn't solve the physics problems created by the engine position (which necessitated the software in the first place).