The story...

Immediately after September 11th, while US airspace was still closed, the White House approved charter flights to rush members of bin Ladins family out of the country. Why weren't they interviewed?

Our take...

Many sites are a little coy about when this flight occurred, but we'll tell you; it was September the 20th. Not such a rush, really, and no, US airspace was not closed.

So who approved the flights? Richard Clarke, who said it was the right decision and he'd do it again. As he's now a major Bush critic it's hard to argue that he'd want to cover up for the President on this point.
http://www.hillnews.com/news/052604/clarke.aspx

The family members weren't simply allowed to leave, either. The 9/11 commission pointed out:

"Twenty-two of the 26 people on the Bin Ladin flight were interviewed by the FBI. Many were asked detailed questions. None of the passengers stated that they had any recent contact with Usama Bin Ladin or knew anything about terrorist activity... The FBI checked a variety of databases for information on the Bin Ladin flight passengers and searched the aircraft".

What's more, by opting to fly the family members volunteered to go through this process. Had they driven across the border to Canada instead, they could have flown home from there with no questions at all.

There were no apparent suspicious circumstances, then, no information incriminating any of these people, and none has appeared since.