Which airlines fly to Cuba? I'm coming from the US, but I don't mind stopping over in another country. I think I have to? Not sure. What's the best city to fly into?
I assume you're visiting Cuba illegally, without an OFAC licence. In that case you have no choice, you MUST fly to Cuba via a 3rd country like Canada, Mexico, Bahamas, etc.
Impossible to give you specific advice when you give no clue where you live in the US...