The accession of Greece to North Atlantic Treaty Organisation saw NATO-funded investments such as the expansion of the 10/28 runway to 2,440 metres (8,010 ft) and the inauguration of a new terminal building in 1965. Major works were undertaken after the war. Works were temporarily abandoned due to the Second World War and the airport opened to civilian traffic in 1948. The first international flight to Thessaloniki landed at the Little Mikra air field, and government efforts at encouraging the growth of civil aviation saw the start of construction of a purpose-built civilian airport at the present location in 1938. There were numerous airfields at the time, including Little Mikra, Big Mikra (which became the current international airport), and the major military airfield of Sedes. The airport was first established as an airfield during the First World War, as part of the allied war effort on the Macedonian front.
To cope with demand, a second terminal is currently under construction as part of a billion-euro investment by Fraport Greece, the company which operates the airport. The Athens–Thessaloniki route is the tenth busiest in the EU with 1.8 million passengers. It is the main airport of Northern Greece and apart from the city of Thessaloniki it also serves the popular tourist destination of Chalkidiki and the surrounding cities of Central Macedonia. It opened in 1930 and was the second-busiest airport in Greece in terms of flights served and the third-busiest in terms of passengers served in 2016, with over 6 million passengers. The airport is the third-largest airport in the country after Athens International Airport and Heraklion International Airport. It is located 13 km (8.1 mi) southeast of the city, in Thermi.
Thessaloniki Airport ( IATA: SKG, ICAO: LGTS), officially Thessaloniki Airport "Makedonia" ( Greek: Κρατικός Αερολιμένας Θεσσαλονίκης "Μακεδονία", romanized: Kratikós Aeroliménas Thessaloníkis "Makedonía") and formerly Mikra Airport, is an international airport serving Thessaloniki, the second-largest city in Greece.