AIRPORT governing body AENA has set up 'feedback machines' in 33 terminals in Spain, including Valencia and all those in the Balearic Islands.
Security checking, baggage reclaim, toilets and numerous other areas now have a number of 'HappyOrNot' units in each, allowing passengers to give their views on levels of service provided.
They feature four round buttons in red, pink, light green and dark green, with faces on them.
These range from wide smiles to downturned mouths, through half-smiles and 'flat' mouths, and passengers who choose to do so press the one they think most reflects how they feel about the services in question.
Smiley or non-smiley faces are used so as to avoid language barrier problems with international travellers.
AENA will then be able to see how the majority rate their experiences and act accordingly.
HappyOrNot operates in over 70 countries, with some of the world's top corporations among its more than 2,000 customers.
The above photograph is from its website, happy-or-not.com.
