The plane departed from Narita at 10 AM.

Literal

Airplane [topic-は] AM-10 [at-に] Narita [from-から] flew-off [polite-ました].

午前10時に成田から飛び立ちました — 飛び立つ is a compound verb meaning 'to fly off, to take wing.' から marks the departure point. Polite past form.