Translation:You have to go to the domestic airport.
Well, you will go to the domestic airpoet should be another answer. As a native speaker from Taiwan, 要 means have to...it depends, I use it for future tense expression more often.
Only to the extent that it is an acceptable alternative in English, and it's definitely not the direct translation. 国内 means within country, so a regional airport in Alaska that has short flights to Canada would not be a domestic airport (in either language).
No. Domestic airport specifically means that it is handling flights within the country only. Such an airport has no customs office. "Regional" just means things that are in the same area. A flight from Boston to Toronto might be considered regional, but it is not domestic. A flight from Seattle to Hawaii is domestic but definitely not regional.
What exactly is the difference in meaning between 内 and 內？
I mean, I can see that one has 入 and the other has what looks like 人，but it turns out both of them are pronounced nèi.