The European Union has wasted tens of million of euro on out-of-the-way, underused airports, an auditors' report has said.
The report examined 20 airport projects in Estonia, Greece, Italy, Poland and Spain which together received €666m of EU funds between 2000 and 2013, the EU Court of Auditors said.
"We found that some airports were not profitable in the long term, some were underused and some were not used at all," said auditor George Pufan in a statement.
The report comes just three days before EU leaders are to green light an ambitious €315bn investment plan, that European Commission head Jean-Claude Juncker says will kick-start growth in Europe.
The plan will in part target thousands of infrastructure projects, including airports, proposed by member states eager to gain funding for pet projects.
In all, the report found that only half of the airports investigated proved worthy of the EU funds, with an estimated €38m wasted completely.
"In Cordoba (Spain), for example, fewer than 7,000 passengers travelled (through the airport) in 2013, against the 179,000 forecast," a statement introducing the report said.
Moreover, seven of the airports, including the Crotone airport in Italy's Calabria region, are not financially sustainable and will require a steady flow of public funds to remain in operation.
"Both the Commission and the Member States must improve the way they invest in our airports by funding only those which are profitable and for which there is a real investment need," Pufan said.
After the report, the commission acknowledged money was wasted, though the way of calculating funds allocated to the projects had now changed.
"We have a radically different approach that will prevent a repeat of these problems," said commission spokesman Jakub Adamowicz.
Investment terms are now "much stricter", he said.