American Airlines said on Thursday it may start charging USD$25 to check a second bag, a move that could spur revenue and cost savings as fuel prices rise.

American said it filed a notice with the Canadian government indicating it may change its bag fee structure in Canada. That country requires 45 days notice to review such a change.

"This filing is only a formality and a decision has not been made by American Airlines to implement a new checked bag fee structure in Canada," a company spokesman said.

If American were to begin charging to check a second bag, it would be the third major US airline to make that change. United Airlines and US Airways began charging the fee earlier this year.

The airline industry has been battered by high fuel costs and low-fare competition that makes it difficult to raise ticket prices. As a result, airlines have been looking for ways to bolster revenue and cut costs.

One popular way to achieve these goals is by charging for items and services that used to be included in the fare. Airlines typically check two bags for free, but analysts forecast all the big carriers soon will begin charging for a second bag.

American's filing in Canada did not indicate what routes the change might affect.