During bad weather, as it could get damaged.
They fly a different flag, because they are a different country, now if they were the same country, they would fly the the US flag.
Yes, it is legal in the US to fly a US, or other flag, from your car. Many people do that.
Texas
Technically, they are on their own soil, so no, they don't have to fly our flag. Just as our embassies don't fly their flag.
It could, but it would be disrespectful.
It is legal to display any flag in the US. This is a matter of freedom of symbolic speech.
No
Any flag could, but it would be disrespectful.
In the United States, no. It is improper to fly another flag above the US flag in the United States. Other countries have similar customs and rules.
It is legal to fly the US flag on a pole in your yard, unless you are somehow doing so in a manner that is disrespectful of it.
The US Flag and POW MIA flag
The US flag is flown at halfmast as symbol of mourning.