American Airlines has been hit with a $1.6 million fine by Department of Transportation for violating tarmac delay rules.
The airline allowed more than two dozen planes to sit on the tarmac for more than three hours without giving passengers the opportunity to deplane.
Under DOT rules airlines are required to allow passengers off a plane when impacted by disruption such as bad weather, and provide refreshments in such cases.
The fine relates to tarmac delays impacting 20 flights at Charlotte in 2013, six at Dallas Fort Worth and one at Shreeveport in 2015.
"Our tarmac rule is meant to prevent passengers from being trapped in aircraft on the ground for hours on end. We will continue to take enforcement action as necessary to ensure passengers are not kept delayed on the tarmac for lengthy periods of time," said US transportation secretary Anthony Foxx.
American has not contested the fine and says it is happy to have the matter resolved.
A large chunk of the fine will not have to be paid.
About $602,000 will be waived as credit for passenger compensation already paid out by the airline and a further $303,000 for a new aircraft tracking surveillance system it installed at Charlotte and Dallas-Fort Worth airports.
