Her husband said he's hoping she'll make a full recovery, calling her "a fighter like nobody else that I know."
The doctors who will help her at a Houston rehab center offered a more sober outlook.
"Not everyone always gets 100 percent restoration, but we help them to get to a new normal," said Carl Josehart, chief executive of the rehab hospital that will be the Arizona congresswoman's home for the next month or two.
Giffords is recovering from a bullet wound to the brain. In her last medical update at University Medical Center in Tucson, doctors said she has scrolled through an iPad, has picked out different colored objects and has moved her lips.
They are unsure whether she is mouthing words, nor do they know how much she is able to see. Her husband, Houston-based astronaut Mark Kelly, believes she has made attempts to speak and can recognize those around her.
"I can just look in her eyes and tell," Kelly said at a final briefing at the Tucson hospital. "She is very aware of the situation."
Giffords is expected to be moved on Friday morning, traveling by ambulance to Davis-Monthan Air Force Base with an escort from a group of motorcycle riders from a Veterans of Foreign Wars post who know her.
Kelly; her mother, Gloria Giffords; trauma surgeon Dr. Peter Rhee, an intensive care unit nurse and Giffords' chief of staff will be among those on the medical flight to William P. Hobby Airport in Houston.
From there, she will be moved by helicopter to TIRR Memorial Hermann hospital. U.S. Capitol police arrived Thursday afternoon to set up extra security measures at the 119-bed facility that is part of the massive Texas Medical Center complex.
Josehart declined to say if Giffords' family had made any special requests, saying, "she's not our patient yet."
The first three days of her stay will involve comprehensive medical and psychological evaluations so a detailed treatment plan can be developed, Josehart said.
Giffords will stay at Memorial Hermann until she no longer needs 24-hour medical care -- the average is one to two months. Then she can continue getting up to five hours a day of physical and other rehab therapies on an outpatient basis, he said.
"It's hard to speculate on the trajectory or course that any one patient will have," he said.
Despite the steady progress, Giffords has a long road to recovery. Doctors are not sure what, if any, disability she will have.
Sometimes, areas of the brain that seem damaged can recover, said Mark Sherer, a neuropsychologist at the rehab center.
"Some of the tissue is temporarily dysfunctional, so the patient appears very impaired very early on after the injury," but may not be permanently damaged, he said.
Giffords' progress was evident Wednesday as she stood on her feet with assistance from medical staff.
During rehabilitation she will have to relearn how to think and plan. It's unclear if she is able to speak. And while she is moving both arms and legs, it's uncertain how much strength she has on her right side; the bullet passed through the left side of her brain, which controls the right side of the body.
The congresswoman's husband said he sees new hope for her recovery every day.
"Every time we interact with her, there's something quite inspiring," he said.
Kelly predicted his wife of three years will walk back into the Arizona hospital soon, and thank everyone who took care of her.
"In two months, you'll see her walking through the front door of this building," he said.
A gunman shot Giffords and 18 other people Jan. 8 as she met with constituents outside a grocery store in Tucson. Six people died and the others wounded. All survivors, except Giffords, have been released from hospitals.
The suspect in the attack, Jared Loughner, 22, of Tucson, is being held in federal custody.
"The last 12 days have been extraordinarily difficult for myself, my family, but not only us," Kelly said. "I think it's been very difficult for the city of Tucson, southern Arizona and our country.
"I don't think we're going to ever fully understand the why and the how and the reason for what happened," he said.
Kelly added that Giffords would be proud of the way Tucson has responded. Memorials continued to grow Thursday outside the hospital, in front of her office and at the scene of the shooting.
"I know one of the first things Gabby is going to want to do as soon as she's able to is start writing thank you notes," he said.