I just came across this in Bill Minutaglio's George W. Bush biography, First Son, and I wish I'd spotted it months ago. It's an account of the last time George W. tried to fly a plane (before his flyboy photo op on May 1, when, reportedly, he briefly took the controls). The pilot of Bush's plane on May 1 said Bush was a bit shaky -- presumably because he hadn't flown in a couple of decades. But Minutaglio says Bush was pretty shaky on that previous flight, in 1976 -- a mere two years after he resigned from the Texas Air National Guard:

...Bush banged on the door of Susie and Don Evans on an otherwise placid Sunday afternoon and suggested to Don that they head out to the airport and spend a few bucks for a spin over the desiccated Permian Basin in a single-engine Cessna....

Evans said he’d love to go flying. At the airport he watched Bush stare at the controls, at the panel, and he realized that Bush -- though not admitting it -- had no idea how to fly the thing properly. After finally figuring out how to launch the plane, Bush pushed the Cessna hard down the runway. Evans screamed, “Give it some gas!” The Cessna’s warning system was blinking and crackling. Bush tried to lift his craft fast, almost as if he were piloting a jet back in the Texas Air National Guard. The plane wobbled into the air, and the unstable maneuvering threatened to shove it into a stall. Now the rented plane was rattling in the sky over Midland. The endless petrochemical complexes, all the aluminum and steel and smoke stacks that pock the Permian Basin, were spiking up just below the aircraft. Bush nervously turned to Evans, put his hand on his knee and blurted in his self-mocking West Texas way, “Okay, Evvie, I’ve got it under control.”

After more seemingly endless moments, he somehow got control of the plane again. He aimed the aircraft down, and the landing was as shaky and brutal as the takeoff. The plane careened off the runway and onto the desert. Evans sighed in relief. Then an unbelieving Evans braced himself as Bush suddenly and unexpectedly spun the plane and bounced back along the runway. Evans stared at Bush. He could see the fear and panic flooding his face. Bush pressed on. Evans had no idea why Bush wanted to go again. The plane wobbled uncertainly back into the West Texas skies, and Bush turned to Evans.

“Hey,” said Bush airily, as if he had just had an original, amusing idea, “let’s fly around Midland.”

The men began cracking up. Bush brought the Cessna back to the airport. It was the last time he flew a plane.

Donald Evans himself -- he's now the secretary of commerce -- is one of Minutaglio's sources for this story. The other source is David Maraniss of The Washington Post -- hardly an ax-grinding lefty. So I think it's safe to say the story's true.