WW2 R.A.F. Squadrons generally consisted of 12 aircraft available, although there were operational variations. Depending on role, the squadron would be made up of 'A' Flight and 'B' Flight, each of 6 operational aircraft. On fighter squadrons, the Flights were sub-divided into sections, eg, Red Section, Blue Section, etc, of 2-3 aircaft, again depending on operational requirements.
Simple machines provide a vocabulary for understanding more complex machines. A simple machine is a mechanical device that changes the direction or magnitude of a force.
Instrument is the word usually applied to tools used in scientific pursuits; as, we speak of a surgeon's or an optician's instruments. An implement is a mechanical agency considered with reference to some specific purpose to which it is adapted; as, an agricultural implement; implements of war. Implement is a less technical and artificial term than tool. The paw of a tiger might be termed a terrible implement, but not a tool.