Dr Jane Deasy, 27, from Dublin, was with her two friends, Dr Aisling Butler and Dr Eithne Walls when the flight crashed into the Atlantic last month, killing all 228 people on board.
Hundreds of mourners packed a church in the south Dublin suburb of Ranelagh to pay a final farewell to the young medic.
In a moving tribute, her younger sister Caragh described her as a princess.
“Jane was an exceptionally special, loving and unique person to all of us,” she said.
“Her qualities were evident, but the ones that stick out in my mind are beautiful, caring, kind, hardworking and generous.
“Her stunning beauty did not go unnoticed, yet she was quite unaware of its extent. In my eyes a real-life princess.”
Dr Deasy’s body was identified earlier this month after being pulled from the ocean, but the remains of her two friends were never recovered.
The families of Dr Butler and Dr Walls attended the service.
Jane had been in Brazil with her two friends and was flying home for a friend’s wedding when the crash occurred.
All three were Trinity College graduates forging out promising careers as doctors.
Caragh said her beloved sister would be remembered as someone devoted to her close-knit family, her parents Joseph and Barbara and other sister Alison.
She was due to start a new job at the Royal Victoria Eye and Ear Hospital in Dublin on July 1, following in the footsteps of her father, a consultant oncologist at Dublin’s Beaumont Hospital.
Caragh also paid tribute to doctors Walls and Butler and Jane’s fiance Alex Creavin, whom she met as a teenager.
“If Jane was a princess, then Alex was most definitely her prince,” she said.