Eheu fugaces labuntur anni. "Alas, the fleeting years glide by." As seen in Horace's Odes.
Fugit hora. "The hour flies." or "Time flies." As seen in Ovid.
Fugit irreparabile tempus. "We cannot stop time in its tracks." or "Irrecoverable time flies away." Tempus fugit is a shortened version of this proverb (or motto), as seen in Vergil.
Fugite fures omnes. "Fly (Flee) all you thieves."