I know school trips (gite scolastiche) are not an Italian thing only.
But as far as I know, in many countries they are limited to elementary school (?), and they are normally excursions or visits to a farm, a park, a museum or another “educational” site.
In Italy we have typical school trip destinations, mainly città d’arte, but also siti archeologici, medieval towns…
Firenze, Bologna, Roma, Assisi, Orvieto, Venezia, Padova, Ravenna, Napoli, Pompei, Ercolano, Amalfi… to name a few.
A gita is normally by bus, or coach, or pullman as we say in Italy (from Pullman Company apparently)