Katie Jaffe loves to fly and comes from a long line of pilots and people in the business of aviation. Her father is a pilot, and her husband, Jordan, is a third-generation pilot.

Her husband is the CEO of Spectre Air Capital, which buys and sells both passenger and cargo planes to businesses and individuals. She is their creative director and design consultant of aviation, which means she designs interiors of the planes.

For her children, Jennifer, 10, Juliet, 8, and Jordan, 2, getting into an airplane piloted by their father or grandfather is normal for them. In fact, Juliet often thinks that she’s piloting the plane because she sits in the cockpit with her dad, Jaffe says.

But when they flew in a commercial plane, Jaffe says, Juliet had so many questions: How many engines did the plane have? Who is piloting the plane if it’s not her dad or grandfather? How could a plane carry this many people?

"Everything I teach them, they come back with more questions," Jaffe says.

Jaffe wanted to answer those questions and teach her own kids about flight and the science behind it. She looked for a children’s book that would do that but couldn’t find one.

Jaffe, 34, grew up in El Paso and came to Austin to go to the University of Texas to study government and stayed. She turned to her mom, Jennifer Lawson, and the two began writing the book together.

"Fly, Fly Again" ($15.95, Greenleaf Book Group Press) breaks down the concepts through a girl named Jenny, who dreamed of flying and is trying to build her own plane. Then she meets a red-tailed hawk and learns about lift. Soon she’s learning about drag and thrust and weight and speed. Oh, and steering is important, too. There’s pitch and roll and yaw.

And once Jenny and her hawk friend have it figured out, they’re ready to move on to the next project (and book): a rocket to space.

The use of a bird to explain it makes the concept accessible to kids, Jaffe says. "When kids are walking around, a simple thing in nature led to this big concept of flight and planes."

To introduce the book, Jaffe asked astronaut Buzz Aldrin to write the foreword. Aldrin has written his own children’s books to keep kids excited about space, and he’s been friends with Jordan Jaffe’s grandmother for years.

Jaffe is now working on the second book (space) and the third book (settling on Mars), as well as an app that will have additional learning materials including an augmented reality component.

"The key is to make it fun," she says.

Jaffe herself was on her way to earning her pilot’s license when she became pregnant with Jordan and had it put it aside for now.

She believes she may see a fourth-generation pilot in her kids. Jennifer’s passion is saving animals, and she wants to be a pilot to save more animals. Juliet wants to be the first astronaut on Mars, and Jordan loves playing with planes.