More: The Department of Transportation is aiming to water down longstanding passenger protections, pushing, for example, to change how prominently airlines display prices in advertising and to clamp down on compensation for disrupted flights.

These recent steps have alarmed consumer groups and elected officials, with some saying that the proposals tilt the scales in favor of the airline industry. In addition, they say, the department is steadily taking a more hands-off approach to policing airlines, and that could end up hurting passengers.