The interest of the Spanish Government in developing airmail during the first decades of the 20th century, led to a study of the possibility of establishing an air mail line to the Balearic Islands. Finally, in 1921, the company Aeromarítima Mallorquina established the postal line Barcelona – Palma, which used seaplanes in the port of Palma de Mallorca. Before the creation of this airline, trials were complete in two flat fields: Son Sant Joan and Son Bonet, both of which were later chosen for the construction of aerodromes. In 1934, the company Aero-Taxi de Mallorca was created with the intention of starting tourist flights to the island, establishing a flight school in Son Sant Joan. A year later, another one was founded in Son Bonet. In May 1935 the company LAPE, Líneas Aéreas Postales Españolas (Spanish Postal Airlines), a predecessor of Iberia; was founded. A month later, in August, the first regular air route between Madrid and Palma, stopping at Valencia, was created using the Son Sant Joan aerodrome. A year later, this line was replaced by a new one connecting Palma and Barcelona. Three years later, Lufthansa and Iberia established new lines in Son Bonet, while Son Sant Joan was beginning to be used by the military. Through the years, Son Bonet became the main civilian airport in the island, while the creation of Son Sant Joan Air Force Base limited further civilian enterprises at the aerodrome. In 1954, the runway was enlarged and paved to enable the operation of F-86 Sabre fighters, which also meant the diversion of the Palma–Llucmajor road. During those years, the first paved taxiways and aprons were built, while Son Bonet received the first big groups of European tourists through the airlines BEA, Air France and Aviaco. The increase in traffic, and the inability to enlarge Son Bonet, led the authors of the 1958 National Airport Plan to propose building a large civilian airport near the Son Sant Joan airbase. The National Airport Council approved this plan the following year and commercial traffic was transferred from Son Bonet to Son Sant Joan. This was the birth of what today is known as the Palma de Mallorca Airport. During that year, a terminal and a civilian apron were built south of the military facilities, along with a VHF communication center. Also, a VOR was installed in the island. Finally, on 7 July 1960, the airport was opened to both domestic and international traffic. Just two weeks later, expansion of the airport was declared urgent by the government, and on summer 1961 the works of extension of the runway and taxiway were started. At the end of the year, more plans were made, including a power plant, a communications centre and fire and rescue facilities. In 1980, passenger growth led to the construction of yet another new terminal building, the current central terminal building. This building is now the airport's primary entrance and exit and houses the airport's checkin and baggage claim areas. Construction started in mid-1993 and it was designed by the Majorcan architect Pere Nicolau Bover. During the construction in 1995, passenger numbers exceeded 15 million. The new terminal finally opened in 1997. Following a decline in passenger numbers at the airport following the September 11 attacks in 2001, passenger numbers rose steadily between 2002 and 2007 when traffic peaked at 23.2 million passengers. From 2007 onward there was a decline in passenger numbers, with 21.1 million using the airport in 2010. Today, Palma de Mallorca airport carries over 29.7 million passengers per year to their destinations, with 178,253 aircraft movements, mostly to mainland Spain, Germany and the United Kingdom. In November 2015, Air Berlin (1978–2017) announced that it would shut down its hub operations at the airport which it had maintained for over ten years.