Do you recall all the bashing of Bush during the 2004 election when John Kerry ran against him and lost. The liberals, backed up by the media were comparing his volunteering in the Texas air guard as cowardly and practically the same as being a draft dodger.
If he had wanted, daddy Bush could have pulled strings and gotten him into the regular army and assigned to a fancy desk job in the pentagon but refused, as he wanted to become a fighter pilot with the intent of being assigned to combat duty in Vietnam.
This article also dispels the stupid dufus image the liberals and media were trying to put across.

"Some of the hyper-libs are saying that Bush's service in the 111th Fighter Interceptor Squadron was the equivalent of draft dodging. They're also saying and the too willing media are buying the idea that Senator Kerry's combat experience would have to make him a better wartime president than Bush. Both points are false. The real issue is what did each of them learn in the Vietnam days, and how those lessons shape their present-day thinking.

First, let's dispense with the idea that Bush was some sort of chicken hawk, hiding in the National Guard while others risked their lives. According to four of the pilots who flew with him, then-Lieutenant George W. Bush was a better-than-average pilot who did a dangerous job very well.

If all you know about flying fighters was learned watching Tom Cruise in Top Gun, you can be forgiven for thinking it's nothing but reckless fun, hard drinking, and a steady stream of beautiful girls. (That's only what the jet jocks want you to believe). The reality is that it's a hazardous business that will kill you long before any enemy gets the chance to if you aren't up to the job. My college roommate, retired Air Force Colonel Ed Atkins, flew fighters for 20 years. Ed told me, "Anybody who thinks that flying fighters is not exhausting physically, demanding intellectually, and tough emotionally just has no clue about the complexity of air combat." He added, "I've flown check rides as everything from a second lieutenant to a colonel. The [flight examiner] doesn't give a damn if your dad was George H.W. Bush, the Chief Justice of the Supreme Court, Jesus or Moses. The only question is, 'can you hack the mission?'" And it's harder to do in some aircraft than others. Dubya had the right stuff."