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 (>> 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 (>> United Continental Holdings, Inc.) 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 (>> Deutsche Lufthansa AG) has also told passengers to expect higher fares.

(Reporting By Karen Jacobs, editing by Dave Zimmerman)