はあいてます

is free; is available

→ は

phrase Uncommon #15,935

is free; is available Used to ask whether a place, room, or time slot is available. With お腹, 空いている means to be hungry.

JA: 今日の午後はあいてますか？

EN: Are you free this afternoon?

I'm free on Sunday.

Is this seat available?

I'm free this Sunday.

Is the counter open?