Planning to travel from Vietnam to Brazil through Turkish Airlines with stopover in Istanbul, or via Qatar Airways with stopover in Doha, Qatar.
Is it possible to stop in Istanbul or Doha without a visa / transit visa? If I checked baggage with any of the possible airlines, should I pick up the luggage in the country of call and check it in again?
Do I have to go through immigration again? Does that require a visa? Or does it automatically follow through my final destination that is in Brazil?