Sellers of online air tickets must indicate the final price as well as surcharges and fees but cannot include flight cancellation insurance by default, the European Court of Justice ruled Thursday.
The ruling followed a complaint by a German consumer-protection group against ebookers.com Deutschland, which sells air travel on the Internet.
When its clients made a booking, the costs listed in addition to the price of the flight contained taxes and fees as well as cancellation insurance, calculated automatically.
A notice at the bottom of the page indicated how to proceed should a customer wish to reject the cancellation insurance, included as a default setting.
The court said that customers must be allowed to choose such optional price supplements that "are neither compulsory nor necessary for the purposes of the flight."
"EU law requires such price supplements to be communicated in a clear, transparent and unambiguous way at the start of each booking process, and that their acceptance must be on an opt-in basis," it said.
Explore further: Google Baseline Study aims to define what a healthy human looks like