This is the 312th most frequent Hungarian word.
el
"El" in Hungarian is a prefix meaning "away" or "off."
Here, 'el' as a prefix with 'megyek' (I go) indicates the action of leaving to reach a destination.
Elmegyek a boltba kenyeret venni.
I'm going to the store to buy bread.
In this sentence, 'el' combined with 'repül' (flies) turns the focus on the manner of flying, emphasizing the passage of time.
Az idő gyorsan elrepül, ha jól szórakozunk.
Time flies quickly when we're having fun.
The word 'el' prefixed to 'adtam' (I gave, sold) specifies the complete finality of the selling action.