if it is fixed, how mani fighters exactly make up a squadron?
this is dependent on the operational requirement. for example our E-2C sqn, there are only 4 of them. as for the fighter sqn the number actually varies from 12 to 20 so therefore there is no such thing as a fixed number of planes per sqn.
Only fixed thing abt the sqn. is that all the planes are of the same type, for example there is the KC-135R sqn with 4 planes, Fokker 50 with 9 planes, TA-4SU in France with 18 planes, etc. . . but thing is I don't know how they split the fighter sqn.s. . .probably make it sort of even. . .
the equivalent of a platoon in the army is called a flight in the air force, for the RSAF fighter sqn, 1 flight consists of 4 planes so 1sqn can consist of 4 or more number of flights.