American Airlines and US Airways Group have joined other big U.S. carriers in adding surcharges to flights in the wake of a disputed European law requiring airlines to pay for aircraft emissions.

Representatives of the two U.S. airlines confirmed on Friday that both have matched a $3 surcharge each way unveiled by Delta Air Lines Inc on fares purchased in the United States for flights between the United States and Europe. The move would help offset the cost of the European Union carbon emissions law that took effect on January 1.

United Continental Holdings also said this week it has matched that charge.

Under the law, airlines touching down or taking off in the European Union and three neighboring nations must acquire permits for the carbon they emit. The measure has drawn opposition from the United States, China and others.

Some industry watchers have said airfares between the United States and Europe could rise as much as $90 as carriers look to pass along the expense to passengers.

Germany's Lufthansa has also told passengers to expect higher fares.

(Reporting By Karen Jacobs, editing by Dave Zimmerman)