Does 这是国际机场吗 without 里 work too?
Yeah, their translation seems to be asking "Is the international airport here?" vs "Is this the international airport?". I also prefer your translation.
Yes, this also works as the meaning is not changed.
When clicking international it ends with 的 but the sentence does not use it. This is misleading
Can you use a 是不是 construction to ask this question? I wrote 这是不是国际的机场。and had it rejected. Just wondered if it was "wrong" wrong, or just "duolingo wrong"