The Airport was used as a military field during the war and, in 1943, additional land was purchased. Subsequent land purchase took place in 1949, 1953 and 1967 to the present Airport dimensions. In the first year of ownership, the City carried out substantial field tile drainage in an endeavour to make the grass landing strips useable in wet weather. Extensions took place in 1943 when the field tile system was further enlarged.

In the early 1950's, the new airline, National Airways, sought to improve its aircraft fleet and a sealed runway was considered necessary.

The original terminal building was constructed during this period. In 1958 the administration of the Airport passed to a Joint Venture between the Crown and the City Council. Subsequent extensions including a 300m extension carried out in December 1975, brought the sealed runway to a length of 1,522 m. The runway operated with this length until it was extended by 380m in 1998 to enable direct flights to Australia with Boeing 737 aircraft. The width of the runway has continued at its established original width of 45 metres.

Structurally, the runway's performance has been enhanced in its lifetime. The first improvement was by means of an asphalt overlay applied in 1963.

In 1975, National Airways Corporation entered into discussions with the City Corporation and Civil Aviation in order to determine if the use of Boeing 737 Aircraft through Palmerston North was a practical proposition. The indicated LCN for Palmerston North Airport was 33 and, after inspections of the runway, it was decided that the Aircraft should be permitted to use the airfield on a limited basis in the knowledge that some considerable overload was going to take place. The Boeing 737 commenced service in late December 1975 with low pressure tyres which gave the aircraft an attributed LCN of 33.

Pressure on the terminal building at this time resulted in the construction of a cafeteria in 1977 as an addition to the old terminal. Because of servicing difficulties, Air New Zealand discontinued the Boeing services in 1977 and the rate of repairs to the runway were seen to drop considerably.

With the reintroduction of Boeing 737 services in December 1978, rapid acceleration in the deterioration of the pavement took place and a major strengthening was completed in 1979 with a 330mm overlay of asphalt concrete, surfaced with a porous 'friction mix' asphalt to improve skid-resistance characteristics.

In late 1979 new aprons were constructed to accommodate the heavier aircraft, and these were further extended in 1987 and 1996.

The 1980's saw the introduction of commuter airlines and in 1989 Ansett NZ LTD introduced its services to the city with Dash 8 aircraft. Ansett eventually became Qantas New Zealand which operated for only a couple of years before its financial collapse in April 2001.

The withdrawal of the Crown from the operations side of the airport saw a contract for Rescue Fire Services tendered in 1988 and these services have been carried out by private contractors since April 1988.

Changes in legislation brought about differential charging and the Airport adopted the first "differential charges" introduced in New Zealand in July 1988.

The Joint Venture partners formed a company, Palmerston North Airport Limited, in December 1989. In January 1990 the company purchased Palmerston North Airport for $5,100,000 and the Joint Venture was wound up.

The old terminal building was hopelessly inadequate both in size and its deteriorating condition. The company relocated the cafeteria extension and it is now used as the NZ Post site. The balance of the building was demolished and replaced with a new terminal building in 1992. The terminal was funded by loan and a domestic Departure Charge of $3 was introduced to help service the additional $3 million debt.

A parallel taxiway, the "No. 3 Taxiway" access to the runway, and the Massey University School of Aviation apron was constructed in 1994.

Air New Zealand withdrew its Boeing 737 services in October 1994 and these were replaced by more frequent services of smaller commuter airlines.

Freedom Air International, a wholly owned subsidiary of Air New Zealand introduced the first commercial trans-Tasman flights on 27 April 1996 using a Boeing 737-300 aircraft to both Brisbane and Sydney.

The main runway was extended from 1,522metres to 1,902metres in early 1998 enabling Freedom Air International to operate commercially viable direct flights to Australia from June 1998. Palmerston North Airport was 'rebranded' as Palmerston North International Airport. In March 1999 QANTAS announced its intention to use Palmerston North International Airport for diversions of trans-Tasman traffic.

The Crown sold its shareholding in Palmerston North Airport Ltd to Central Avion Holdings Ltd in January 1999. The Palmerston North City Council subsequently purchased those shares in November 2006 to then hold 100% of the company's shares.

Freedom Air announced in July 1999 its intention to double the size of its operations later that year in response to growth opportunities. As the planned introduction of a trebling in international services at Palmerston North, Palmerston North Airport Ltd embarked on a $4.2m development to provide larger terminal facilities, increased aircraft apron, and additional carparking. The first stage of development, the first direct flight to Melbourne and a weekly service to the Gold Coast were celebrated on 19 December 1999.

A twice weekly service to Fiji commenced on 29 March 2000, but was suspended following a coup in May of that year. The service to Nadi was re-introduced by Freedom Air on 15 May 2004 and withdrawn two years later following further unsettled politics in Fiji.

Major terminal building extensions were officially opened on Sunday 11 June 2000 by the Mayors of 12 of the Districts served by Palmerston North International Airport.

The airport's carpark capacity was increased by 70% to 616 car parks in December 2004.

The first Boeing 767 aircraft to use Palmerston North International Airport was a Royal Brunei B767 on 10 March 2003.

Freedom Air replaced their 141 seat B737-300 aircraft with Airbus A320 aircraft configured with 150 seats in October 2005.

Origin Pacific Airways and Air New Zealand expanded their services, and by the end of 2002 domestic passenger loads exceeded those that existed before the demise of Qantas NZ. However, Origin Pacific ran into financial difficulties and by 10 August 2006 had stopped operations. Domestic passenger numbers through the airport continued to grow despite Origin's departure.

On 6 September 2007 Air New Zealand announced that it would be withdrawing all Freedom Air services from 30 March 2008. On 30 October 2007 Ozjet Airlines announced their intention to start trans-Tasman services from Palmerston North International Airport from late March 2008, but on 27 March 2008 just three days before its launch, merger talks between OzJet and another airline scuttled that service.

From the time of the first international sevices in 1996, the company advocated that the distinction of regional airports from the metropolitan airports for international border processing cost recovery was unfair, and in some aspects illegal.

Unsuccessful approaches to the Government agencies, and the Ministers concerned, saw Palmerston North Airport Ltd join with Waikato Regional Airport Ltd and Freedom Air to challenge the legality of the MAF Biosecurity charges that were being recovered at regional ports, while at Auckland, Wellington and Christchurch these services were largely met by all New Zealand taxpayers.

Three court hearings followed. A High Court decision in February 2001 upheld the airports' claims; a Court of Appeal decision in March 2002 overturned the High Cout decision; and eventually an appeal to the Privy Council was heard on 29 and 30 April 2003.

The Privy Council decision of 30 June 2003 overturned the Court of Appeal decision and reinstated the decisions of the High Court. The MAF system of charging was found to be unfair and unlawful.

However the nine-year battle for fair treatment on border services came to a head when, on 13 April 2005, the Government announced the outcome of a comprehensive review of border cost recovery policy which established all seven New Zealand international airports on an even footing from 1 October 2005. As a consequence, the international Departure Charge of $25 was amended to apply only to passengers of 12 years of age and over, and landing charges for international aircraft were reduced significantly.