On April 21st, an Iranian F-27 maritime patrol aircraft flew very close to the American aircraft carrier, the USS Eisenhower, in the Sea of Oman. The F-27 is a 19 ton, twin engine transport that has been used mainly for transport by the Iranian forces (which has twenty of them serving in the army, navy and air force). In this case, the F-27 was believed to be a navy patrol aircraft. The American carrier tracked the F-27 continuously once it was about 200 kilometers away. The F-27 came in very close (about 1,000 meters away, at an altitude of some one hundred meters.)
Since the carrier was in international waters, and had not announced any flight restrictions (for combat operations or whatever, warships can do this, for short periods, to keep commercial aircraft and ships away), the Iranian aircraft was allowed to get this close. But there is always the danger of a suicide bomb attack. The F-27 could be crammed with several tons of explosives, which would do a lot of damage to an aircraft carrier. With the F-27 only a kilometers away, a sharp turn towards the carrier would have the aircraft hitting the ship in less than ten seconds. Possibly enough time for the Sea Sparrow missiles from the carrier, or escort ships, to do enough damage to stop the suicide Fokker from arriving, but maybe not.
Iranian later claimed the flyby as a great military achievement, and mentioned that they were only there to take pictures.