Air travel recommendations for the 21st century.
Each student flight is booked either by MISTI Brazil or the student. This is discussed at the meeting with the Program Manager. For summer internships, most students book flights in April after they have confirmed their internships dates.
If your stay is fewer than 90 days and you do not require an entry visa, it should be possible for you stay in Brazil to travel after your internship ends (at your own expense).