Airport modernisation is an expensive deal for its users, as it involves the AAI share of the revenue becoming a pass-through. An increase of close to three and half times in user charges at the Indira Gandhi International Airport (IGI) in New Delhi should come as no surprise. It is, after all, an inevitable outcome of an utterly perverse revenue-share system adopted for awarding of such projects under the public-private-partnership (PPP) model.