So far this is an unsubstantiated rumour. It may have some substance or it might just be propaganda for the purpose of spreading fear and panic and thus burying bad news.
“The United States is on alert and has deployed military assets to defend the Atlantic coastline from New York to Charleston from attack by a cruise type missile or low flying aircraft.
Heightened security measures began with Israels increasing threats against Iran but increased with the mysterious disappearance of Malaysian Airlines flight 370.
Sources at the highest levels of the US military and intelligence community cite the possibility of a terror bombing, even using nuclear weapons, most likely to be submarine launched. This is what is being defended against.
However, the plot, we have been informed, was to include a seemingly hijacked airliner which would be blamed on Iranians, as stated by Joel Rosenberg while speaking with Greta van Susteren on Fox News, March 18th. Rosenberg claimed the Iranians hijacked the plane to attack Israel.
The US, however, believes someone other than Iran is planning an attack, on the US, not Israel, and planning to blame Iran.”