A surge in pre-9/11 airline Puts is most certainly not known to be an urban legend. One primary source of this so called "urban legend" is the "9/11 Commission Report" page 499 {footnote 130}.

http://books.google.com/books?id=fNqdmUnqTJUC&pg=RA1-PA499&lpg=RA1-PA499&dq=highly+publicized+allegations+of+insider+trading+in+advance+of+%229+11%22+generally&source=web&ots=ItnrSDunAk&sig=79v2vsxnVTZH-p3ut4xFQVOHFJU

Highly publicized allegations of insider trading in advance of 9/11 generally rest on reports of unusual pre-9/11 trading activity in companies whose stock plummeted after the attacks. Some unusual trading did in fact occur, but each such trade proved to have an innocuous explanation.

For example, the volume of put options — instruments that pay off only when a stock drops in price — surged in the parent companies of United Airlines on September 6 and American Airlines on September 10 — highly suspicious trading on its face. Yet, further investigation has revealed that the trading had no connection with 9/11.

A single U.S.-based institutional investor with no conceivable ties to al Qaeda purchased 95 percent of the UAL puts on September 6 as part of a trading strategy that also included buying 115,000 shares of American on September 10.

Similarly, much of the seemingly suspicious trading in American on September 10 was traced to a specific U.S.-based options trading newsletter, faxed to its subscribers on Sunday, September 9, which recommended these trades.

The SEC and FBI, aided by other agencies and the securities industry, devoted enormous resources to investigating this issue, including securing the cooperation of many foreign governments. These investigators have found that the apparently suspicious consistently proved innocuous.