HTFA in the context of the US Navy typically stands for "Helicopter Training Flight Academy." It refers to a program or unit focused on training personnel in helicopter operations and related activities. The US Navy has various training programs to ensure that its pilots and crew members are proficient in flying and operating helicopters.
I haven't heard that term when relating to the US Navy. But in the Royal Navy SDG is a scubadiver
SEa Air and Land
submersible boat
Landing Helicopter Assault
The term "NAR" doesn't refer to a Navy ship - it's the standard Navy acronym for Naval Air Reserve.
carpenter's mate first class
Possibly a Flight Engineer
The US Navy SEALS is a Special Operations Group of the US Navy
China has the largest if you count by "tonnage", although this does not automatically mean they have the most "powerful" navy. The US Navy is the most powerful in Asia, although it itself is not an Asian country.
Not sure but I would think the NAVY
In 1798, the U.S. Navy and U.S. Marine Corps were created
The US Navy.