Hello evryone, here I’ve done a list of commercial Italian airport, If some airport are missing, I will update it.
North Italy: 
Friuli Venezia Giulia:
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Trieste (TRS/LIPQ)
Veneto:
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Venice (VCE/LIPZ)
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Treviso (TSF/LIPH)
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Verona (VRN/LIPX)
Trentino Alto Adige:
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Bolzano (BLO/LIPB)
Lombardia:
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Milan Malpensa (MXP/LIMC)
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Milan Linate (LIN/LIML)
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Bergamo (BGY/LIME)
Piemonte:
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Turin (TRN/LIMF)
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Cuneo (CUF/LIMZ)
Liguria:
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Genoa (GOA/LIMJ)
Emilia Romagna:
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Parma (PMF/LIMP)
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Bologna (BLQ/LIPE)
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Forlì (FRL/LIPK)
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Rimini (RMI/LIPR)
Center Italy 
Toscana:
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Florence (FLR/LIRQ)
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Pisa (PSA/LIRP)
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Elba Island (EBA/LIRJ)
Umbria:
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Perugia (PEG/LIRZ)
Marche:
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Ancona (AOI/LIPY)
Lazio:
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Rome Fiumicino (FCO/LIRF)
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Rome Ciampino (CIA/LIRA)
South Italy 
Campania:
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Naples (NAP/LIRN)
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Salerno (QSR/LIRI)
Puglia:
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Bari (BRI/LIBD)
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Brindisi (BDS/LIBR)
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Foggia (FOG/LIBF)
Calabria:
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Lamezia Terme (SUF/LICA)
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Crotone (CRV/LIBC)
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Reggio Calabria (REG/LICR)
Islans 
Sicily:
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Catania (CTA/LICC)
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Palermo (PMO/LICJ)
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Trapani (TPS/LICT)
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Comiso (CMY/LICB)
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Pantelleria (PNL/LICG)
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Lampedusa (LMP/LICD)
Sardinia:
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Cagliari (CAG/LIEE)
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Alghero (AHO/LIEA)
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Olbia (OLB/LIEO)
Currently only Bari (BRI/LIBD) is in game.
Ps. This is a list of especially Commercial airport that are current in use for commercial connection. Some airport that are missing are because in past they had commercial flight, but now they only operate private and civilian plane. I haven’t add in this post the Military airport.
If some airport are missing from this list, it will be updated.