The United States Navy

Nuclear weapons in the U.S. Navy arsenal are deployed through ballistic missile submarines and aircraft. The Ohio-class submarine carries the latest iteration of the Trident missile, a three stage, underwater launched, nuclear ICBM with MIRV capability; the current Trident II (D5) version is expected to be in service past 2020. The Navy’s other nuclear weapon is the air-deployed B61 nuclear bomb. The B61 is a thermonuclear device that can be dropped by strike aircraft such as the F/A-18 Hornet and Super Hornet at high speed from a large range of altitudes. It can be released through free-fall or parachute and can be set to detonate in the air or on the ground.
Naval Jack
The current naval jack of the United States is the First Navy Jack, traditionally regarded as having been used during the American Revolutionary War. On 31 May 2002, Secretary of the Navy Gordon England directed all U.S. naval ships to fly the First Navy Jack for the duration of the "War on Terror". Many ships chose to shift colors later that year on the first anniversary of the September 11, 2001 attacks. The previous naval jack was a blue field with 50 white stars, identical to the canton of the ensign (the flag of the United States) both in appearance and size, and continues to remain in use with vessels of the U.S. Coast Guard and National Oceanic and Atmospheric Administration. A jack of similar design was used in 1794, though with 13 stars arranged in a 3–2–3–2–3 pattern. When a ship is moored or anchored, the jack is flown from the bow of the ship while the ensign is flown from the stern. When underway, the ensign is raised on the mainmast. The First Naval Jack, however, has always been flown on the oldest ship in the active American fleet, currently the USS Constitution.