How works the system of frequency for aircraft commercial Airline
I think you have a misunderstanding on how individual radio frequencies are used.  

Individual radio frequencies are not assigned to aircraft.  They are assigned to Air Traffic Control facilities like Control Towers or Area Control centers.  

Each aircraft will have it's own "radio licence" but they can tune in any frequency that is needed for both transmitting and receiving. All aircraft in a specific area will use the same frequency as assigned by ATC. You may have 20 or 30 aircraft on the same frequency, but only one aircraft should be transmitting at any time. 

There is a lot of congestion on the radios in a busy sector and "CPDLC" (Controller–pilot data link communications) is gradually being introduced in many areas. This allows ATC and the pilot to communicate directly via data-link text messages. 

In some areas where there is no ATC control, aircraft can monitor or communicate on a common "air to air" frequency.  123.45 is used in some areas.