The cancellations were felt most acutely in Chicago, where ice and snow briefly halted all flights on Tuesday afternoon. Airports elsewhere in the Midwest and the Northeast were also affected.
Bob Sauer said that his 50-foot cedar trees had acted on the same scientific principle as an airbag, disrupting the door plug’s fall in an act known in physics as impulse.
Boeing and the Federal Aviation Administration issued technical instructions to airlines two days after a part of a plane was blown out near Portland, Ore.
Two days after a chunk of the fuselage blew out of one of the planes, the F.A.A. and the aircraft maker are still negotiating what to tell the airlines to do.