Giffords chief of staff Pia Carusone confirmed to The Associated Press that she and the congresswoman boarded a jet in Houston. She declined to comment further, except to say she will be flying with Giffords and they will arrive in Cape Canaveral together.
"We haven't taken off yet but we're at the air field," Carusone said minutes before they were to take off.
Her husband, Mark Kelly, is leading the shuttle crew that is set to lift off on Friday in an event that President Barack Obama will also attend. Kelly arrived at NASA's launch site Tuesday to prepare for the nation's next-to-last space shuttle mission.
"It's something she's been looking forward to for a long time," Kelly said of his wife's attendance at the launch. "She's been working really hard to make sure that her doctors would permit her to come. She's more than medically ready to be here, and she's excited about making this trip."