A jaw-dropping sight caught on tape as a 747 jumbo jet buzzed the Golden Gate Bridge, flying just a few hundred feet over one of the nation's most iconic landmarks.
It turned out to be a publicity stunt for United Airlines as part of San Francisco's "Fleet Week" festivities.
But some people say the disturbing video reminded them of 9/11.
"Perhaps it's my own jitters having lived in Washington, D.C. on 9/11, but the imagery of that day is hard to shake," one blogger writes.
Another says: "If that fly by had happened over the Brooklyn Bridge, people would have FREAKED OUT."
In fact, in 2009 New York City was in a state of panic when Air Force One buzzed low over the city's skyline so photographers could snap photos of the President's plane.
On the West Coast, other bloggers see the latest flyover as being no big deal.
One writes: "It was an air show, a 747 jet flew over the bay...Sorry folks, 9/11 - REALLY???"
United Airlines told INSIDE EDITION in a statement: "The fly-by was conducted as part of a well-publicized air show and with the utmost consideration to the safety of the public and the aircraft."
Aviation expert Barry Schiff weighed in, saying, "This was a well-planned event. All contingencies are considered and it's made to be as safe as humanly possible."