Flights in and around Europe are now liable for their carbon emissions. Airlines are now being charged fees to buy carbon credits and that cost will likely be passed on to passengers.
The cost could add up to as much as $16 each way.
Under a carbon trading system, companies have to hold carbon credits to emit greenhouse gases. It's similar to a stock exchange where companies buy and sell carbon credits based on the amount of carbon they emit.
The goal is to push industries toward greener technology.