Noise pollution around airports is one of the most important problems in environmental acoustics. The incessant development of modern societies is continuously increasing the demand for air transport, and airports have to grow to adapt their operational capacity to the new requirements. On the other hand, the economic activity related to airports is closely linked to the expansion of built-up areas around them. Consequently, two completely incompatible land uses are forced to coexist, causing airport capacity to remain limited while the inhabitants do not cease to be annoyed by aircraft noise. Although there are several international initiatives setting the focus on the reduction of noise at the source, people living in residential areas around airports need urgent solutions. Among others, the implementation of sound insulation programs is one of the most widely-adopted solutions worldwide, as it allows a reduction of sound levels in the interior of dwellings, while the operational capacity of the airport remains unaffected. The definition and application of a sound insulation program is a very complex process that needs to manage several opposing factors: health, annoyance, airport capacity, economic costs of insulation measures … In this paper we describe the case of Spanish airport insulation programs. We set the focus on a concise description of the full process, from the creation of noise maps, to the checking of installed soundproofing measures, as carried out by the Spanish administration. As a result of this process, thousands of dwellings and houses have been acoustically insulated to meet indoor noise comfort criteria in Madrid, Mallorca and Malaga airports, among others.