To say how you get somewhere, use andare + in + the means of transport with NO article: in treno, in autobus, in macchina, in aereo, in bici. The exception is travelling under your own power, which takes a: a piedi (on foot), a cavallo (on horseback). The destination keeps its own preposition (a Firenze, al lavoro, all'aeroporto), so both can appear in the same sentence.
Examples
- Vado al lavoro in autobus.
- I go to work by bus.
- Domani andiamo a Firenze in treno.
- Tomorrow we're going to Florence by train.
- Il museo è vicino: ci andiamo a piedi.
- The museum is close: we'll walk there.
- Preferisco andare in aereo perché ci mette meno tempo.
- I prefer to fly because it takes less time.
The mistake to avoid
Learners add an article after in — it's vado in macchina, never "vado in la macchina"; and walking is a piedi, not "in piedi" (which means standing up).
Where this fits in
Spostarsi, Italian A2: Muoversi in città e in viaggio: trasporti, indicazioni stradali, albergo e biglietti.