03/21/2007 at 10:30 AM EDT
Angelina Jolie is bringing her new son home.
The actress and 3-year-old Pax Thien Jolie, whom she adopted last week
from an orphanage in Ho Chi Minh City, left Hanoi's Noi Bai Airport in a private jet on Wednesday, bound for home – and, for Pax, a new life – in the U.S.
Jolie, 31, understands the challenges her new son will face as the latest addition to the world's most famous multicultural family. "You can imagine what courage it takes to be in all new surroundings, with new people and a new language," she tells PEOPLE in its new issue. "He is very strong."
But she is committed to making his transition as smooth as possible. "It will take him a while to realize he has a family," she says, "and that his new life is permanent and that it won't keep changing."
The boy with the sweetly shy smile and the big brown eyes joins big brother Maddox, 5 (adopted from Cambodia), sister Zahara, 2 (adopted from Ethiopia) and 10-month-old Shiloh, the daughter born to Jolie and Brad Pitt, 43, in May.
As for Dad, because Vietnamese regulations don't allow unmarried couples to co-adopt, Jolie adopted Pax as a single parent while Pitt remained in Los Angeles, where he is filming The Curious Case of Benjamin Button
. "He has specific days on the movie that couldn't be changed or production would run over," says his rep.
But Jolie still made sure to bring a welcoming committee: Joined by Maddox and Zahara – Shiloh has been on the Button
set every day with her father – the new mom used her first few days with Pax to begin gently bonding with him and to allow her other kids to do the same.
"We are slowly beginning to build his trust and bond," Jolie says, "but it will feel complete only when we are all together."
For exclusive photos – plus details on Angelina and Pax's first moments together, what Pax's life was like at the orphanage and more – pick up this week's
PEOPLE, on newsstands Friday.