In an act that the US would call terrorism if committed by any other country, the USS Vicennes blew an Iranian commercial airliner out of the sky on July 3, 1988. We have never even apologized or accepted legal liability.
A wikipedia summary of the pertinent details with emphasis added by this author follows the orange smoke
Iran Air Flight 655 was an Iran Air civilian passenger flight from Tehran to Dubai. On 3 July 1988, the aircraft operating this route was shot down by the United States Navy guided missile cruiser USS Vincennes. The incident took place in Iranian airspace, over Iran's territorial waters in the Persian Gulf, and on the flight's usual flight path. The aircraft, an Airbus A300 B2-203, was destroyed by SM-2MR surface-to-air missiles fired from Vincennes.
All 290 on board, including 66 children and 16 crew, died.[1] This event ranks eighth among the deadliest disasters in aviation history, 11th if including the 9/11 attacks, which include ground casualties; the incident retains the highest death toll of any aviation incident in the Persian Gulf. The cruiser Vincennes had entered Iranian territorial waters after one of its helicopters drew warning fire from Iranian speedboats operating within Iranian territorial limits.[2][3]
According to the Iranian government, Vincennes negligently shot down the civilian aircraft: the airliner was making IFF squawks in Mode III (not Mode II used by Iranian military planes), a signal that identified it as a civilian craft.[4][5]
Iran Air Flight 655
There really isn't much more that one can say except that we are all lucky that the US government didn't manage to parlay this event into another Tonkin Gulf.