The US Supreme Court denied a petition by low-cost carriers asking the court to reject a regulation requiring that taxes be displayed as part of the fare price in advertising.

Spirit Airlines, joined by Southwest Airlines and Allegiant Air, had appealed a US federal appeals court ruling that upheld a Dept. of Transportation (DOT) rule mandating that all taxes be included when air fares are advertised or displayed on websites. The airlines can provide a breakdown of the taxes, but under the DOT rule the full price—including taxes—must be the largest and most prominently displayed figure.

The Supreme Court said Monday it has decided not to hear the case, which essentially cements the lower-court’s ruling and leaves airlines with little recourse but to comply. Spirit and the other airlines argued that the DOT requirement restricts carriers’ ability to inform the public of the tax burden on flight tickets.

Airlines for America (A4A) president and CEO Nicholas Calio said recently that a $300 flight ticket typically contains $61 in taxes and fees, and argued that airlines shouldn’t be required to advertise taxes as part of the fare price. “In no other industry is pricing done that way,” he said. “This allows the government to hide the ball on taxes and fees.”