In the modern sense, fleets are usually, but not necessarily, permanent formations and are generally assigned to a particular ocean or sea.
Most fleets are named after that ocean or sea, but the convention in the United States Navy is to use numbers.
[3] In more modern times, the squadrons are typically composed of homogeneous groups of the same class of warship, such as battleships or cruisers.
Modern fleets combine surface warships, submarines, support ships, and ship-based aircraft to conduct naval operations at sea.
The largest naval powers operate aircraft carriers as their fleets' primary capital ships, with battleships having become obsolete since the Second World War.