The Republican presidential hopeful said he was proud of his stateside military service and said had his unit from the Texas Air National Guard been called up, he would have gone overseas.

" I asked to become a pilot. I met the qualifications, and I ended up becoming an F-102 pilot," said Mr Bush, before a Fourth of July parade on Sunday.

The Los Angeles Times said that in the late 60s, Mr Bush had jumped into the officer ranks when he was just out of basic training. It said he did not have the credentials that many other officers possessed.

'Absolutely qualified'

But a spokeswoman for Mr Bush said the Texas Air National Guard was short of pilots, and a candidate had to be a commissioned officer to go to flight school. "The military found him absolutely qualified to be commissioned," she said.

The Times said a historian for the Texas Air National Guard had told the newspaper that Bush's unit had 27 pilots when he applied, two short of its authorised quota. But he said there were two other pilots in training and another waiting to transfer.

Mr Bush's father, the former president George Bush was a congressman from Houston at the time of his son's application.

Mr Bush junior said that he joined the Air National Guard rather than volunteer for combat duty because he wanted to learn to fly fighter planes like his father.

During the Vietnam era, joining the National Guard was seen by many people as a way to avoid the draft and combat duty.