Not so long ago, the idea that a full-service carrier would rely on a no-frills airline to provide it with passengers would have been laughable.

The difference in service standards between, say, British Airways on the one hand and Ryanair on the other are as different as chalk and cheese.

However, over the past few years the service gap between carriers such as BA and Lufthansa compared with the likes of Ryanair and Easyjet has narrowed. All airlines are anxious to keep cutting costs while continuing to attract passengers.