When Pauline Hanson flew in a new $110,000 plane to a Reclaim Australia rally in Rockhampton in July 2015, she proudly announced it as her own.

“Hanson takes maiden flight in her new plane,” her media release was headed, before describing it as One Nation “launching their new plane”.

Just whose plane it is and for what purpose are a matter of contention almost two years later.

The Australian Electoral Commission has been reviewing allegations the plane represents a gift from One Nation’s biggest recent donor, the Victorian developer Bill McNee, and should have been declared as such.

Hanson and her chief of staff, James Ashby, give a different account of the plane’s ownership and use and say all appropriate electoral disclosures have been made.

Queensland Labor senator Murray Watt, in writing to the AEC last month, said the allegations of an undeclared donor gift were “very serious”.

The first public mention of the plane was in Hanson’s release on 15 July 2015.

She invited media and public to see it take off for the Reclaim Australia rally the next day from Caloundra airport.

“I am proud to announce Pauline Hanson’s One Nation will be launching their new plane just finished being built by an Australian company last week,” Hanson said. “I am thankful to now have a plane as this will enable me to visit people around the state, and interstate, including those in small remote communities who have never had their representative take the time to visit them.”

Hanson’s pilot through the campaign was Ashby, a licensed recreational pilot and controversial former Liberal National party staffer, who became her chief of staff. She was elected a senator in July 2016.

Hanson’s first Senate speech was witnessed by McNee and his wife, Renata, sitting beside Ashby in the gallery.

“A couple of strangers came along at the right time, helped me spread my wings and gave me the support and assistance I needed that now sees me standing on this floor today,” Hanson said. “These people are no longer strangers but dear friends welcome at home any time for another lamb roast. Thank you Bill and Renata.”

Last month, former One Nation treasurer Ian Nelson told ABC’s Four Corners that McNee discussed providing a plane for Hanson at her home over roast dinner on 11 April 2015.

Nelson said: “[Ashby] just kept saying, ‘I’m a pilot, we should be flying Pauline around’ and Bill said, ‘We’ll have to get you a plane then.’”

Four Corners reported that Ashby texted a party official on 13 April to say: “We need to talk to Bill about funding it.”

The official responded: “We had a good chat with Bill. I think Pauline’s going to go for the plane.”

On 21 April, McNee emailed Ashby: “James we will sort out the plane tomorrow as well.”

Insurance documents obtained by Four Corners showed the plane, a Jabiru J230D, was insured in the name of James Ashby and his Black Bull business trust. The purpose of the plane, insured for a maximum value of $110,000, was “business”.

McNee’s company Vicland donated almost $70,000 to One Nation in early 2015 – mostly in the form of a gift of $57,720 in rent on the party’s inner Brisbane office space.

McNee told Four Corners there had been “no financial support or assistance to any political party outside what is publicly disclosed and already well known”.

What James does in his business is his business, the plane has never been given to the party. Pauline Hanson

McNee separately told Fairfax that he “did not have a clue” what had been done with the money he gave One Nation and that he had stopped giving political donations.

Nelson told Four Corners that, when Hanson told him it was her plane, he urged her to declare it in line with donation rules but she told him “don’t worry about it”.

“I said, ‘Well, did Bill McNee buy that plane for the party, did he buy it for you or did she buy it for James Ashby?’ And she just looked at me and walked away.”

Nelson said the purpose of the plane was “for the One Nation party, to ferry Pauline around” so it “should have been disclosed”.

Watt wrote to the AEC on 4 April urging it to investigate an “alleged breach of financial disclosure requirements” by One Nation.

He said it was “very important that all political parties in Australia comply with election laws, especially in relation to donations”.

“People are rightly concerned to make sure that outside donors aren’t buying inappropriate influence.”

Ashby then declared it was “my aircraft” and the AEC could review the party’s returns “whenever they see fit”.

“The hours flown for party business on board my aircraft have been declared in accordance with the AEC rules,” he told the ABC.

Australian electoral commissioner Tom Rogers wrote to Watt on 5 April to say the AEC was aware of allegations in the media and “this information is now being reviewed in the context of disclosure provisions” of the act.

On Monday, contrary to her 2015 description of the plane as her and One Nation’s, Hanson said the Jabiru bearing her name and logo was Ashby’s.

McNee had sold the plane to Ashby, who runs a printing business from his parents’ Sunshine Coast property, to use for his business, Hanson told Sky News.

“He found out James was a pilot, he thought, ‘Here’s a great opportunity’,” she said. “What James does in his business is his business, the plane has never been given to the party.”

Ashby said his company bought the plane and it was “the second plane I’ve owned”.

“I’m very capable of buying my own planes,” he said. “And yes, the hours used for party use have been declared.”

Hanson, describing the plane in January as “my plane, well, the party’s plane”, told Sky News she had paid personally for its fuel since her election.

One Nation declared a payment of $1,187 for “Jabiru aircraft service” to the Electoral Commission of Queensland in its return for the first half of 2016.

Whatever the AEC ruling on the plane – whether it was intended to be a gift for One Nation, or simply an asset of Ashby’s, which now makes him in effect a donor to the party – it’s a controversy that electoral law observers consider unlikely to trigger anyone’s downfall through its legal implications.

Under the Commonwealth Electoral Act 1918, providing false or misleading information about political donations at worst brings a fine of $10,000.

Providing false or misleading information during a compliance review or investigation by the AEC carries a fine of $1,000 and/or six months in jail.

Should One Nation choose alternately to make a disclosure of a political donation in kind, no matter how belated, there would be ample precedent from both major parties.

But the AEC, with its forensic accounting powers, has an interest in making sure its public records of disclosures, no matter how historical, are accurate. The AEC does not make comment on ongoing individual investigations.

Nelson told Guardian Australian he had not been contacted by the AEC, which left him “bewildered”.