The top executive of a major US airline has voiced opposition to a change in security regulations that will allow small pocket knives, baseball bats and other previously banned sporting equipment aboard airplanes. \"These items have been banned for more than 11 years and will add little value to the customer security process flow in relation to the additional risk for our cabin staff and customers,\" Delta Air Lines CEO Richard Anderson wrote to the head of the Transportation Security Administration on Thursday. The missive followed a decision by the TSA to allow pocket knives and other sporting equipment -- banned on US flights since the September 11, 2001 attacks -- back in aircraft cabins. Passengers will be able to carry knives with folding blades 2.36 inches (6 centimeters) or shorter, as well as sporting goods such as golf clubs, hockey clubs, and novelty-sized baseball bats, the federal agency said. TSA chief John Pistole said the new guidelines, which come into effect on April 25, would bring US security regulations into line with international standards. But Anderson said his airline\'s flight attendants \"share legitimate concerns\" about the decision. \"If the purpose is to increase security checkpoint flow, there are much more effective steps we can take together to streamline the security checkpoints with risk-based screening mechanisms,\" Anderson said in the letter to Pistole.