Virgin Group Chairman Richard Branson has said that the US Dept. of Transportation’s granting American Airlines (AA), British Airways (BA) and other oneworld carriers antitrust immunity on transatlantic services “would create a monster monopoly on key routes between London Heathrow and the US.”

In a speech in Washington, he said BA/AA would control “nearly half of all takeoff and landing slots at London Heathrow” and that antitrust immunity would prove “disastrous” for the airline industry and consumers.

“It’s clear that the application for a merger between BA and AA must be rejected,” he said, adding, “What is before the regulators today is the future of a competitive international aviation industry.”

American Airlines responded by accusing Branson of “trotting out old, outdated arguments that do not reflect the current environment and trying to sensationalise the matter.”