SPAIN (Agencies) The war of attrition that has been going on for some time between air traffic controllers and the airport authority AENA seems to have opened another front. The airlines federation, Asociación de Compañías Españolas de Transporte Aéreo (ACETA) has decided to break its silence on the subject by announcing its 'deepest concern' about the 'significant increase' in the number of delays experienced by its members at Spanish airports, a problem that is impacting directly on the 'quality of service' they can offer, as well as on their costs. AENA, on the other hand, insists that punctuality has improved by 17% since June last year, a figure not shared in the least by the airlines, who quote the latest reports from the European security entity Eurocontrol. These show Gran Canaria, Tenerife and Madrid Barajas heading the list of delays. "There are definitely problems and we have noticed siginificant increase ìn delays+ over the last few weeks," says the association, which includes airlines such as IAG (ex-Iberia), Air Europa, Air Nostrum, Vueling and Binter Canarias, among others.