Katter's Australia Party MPs have told a Townsville court they were unaware a charter flight service they used was allegedly operating illegally.
North Queensland Josh Hoch is on trial accused of flying KAP members Bob Katter, Robbie Katter and Shane Knuth in chartered planes illegally and doing so without an air operating certificate over a four-year period.
Hoch has pleaded not guilty to 14 counts including dishonestly gaining benefit and performing a duty without authorisation between 2011 and 2015.
Traeger state MP Robbie Katter told the District Court via video link on Thursday his interactions with Koch were professionally based and involved the use of chartered flight operators within his electorate.
He said he used the service between five and 10 times through the parliamentary general travel allowance but it was organised by his office.
"I do recall saying there's a new operator in town and look to use them, because I try and use other operators and share the love or share the patronage to the charter operators in Mount Isa," Mr Katter said.
"I sign a document at the end of each financial year to verify those flights were for this purpose but that has nothing to do with the authenticity of the operator."
Koch's trial also heard from a Mount Isa-based pilot for the Royal Flying Doctor Service, Luke Westerhuis.
He told the court of a conversation with Koch in February 2016 at Mount Isa Airport.
Mr Westerhuis asked how Koch's application for an air operating certificate was going.
"Josh replied that he had just recently gained that qualification from CASA (Civil Aviation Safety Authority) to have an AOC," Mr Westerhuis told the court.
He followed up in that conversation by asking about a charter flight two months earlier with Bob Katter in Innisfail and whether that fell under the AOC.
"His reply was 'no', because he didn't have an AOC," Mr Westerhuis said.
"Then I asked him if he was doing it under cost sharing or under private operations, and he smirked and sort of was like 'yeah, that's how we did it, we are family friends'."
State member for Hill Shane Knuth gave evidence briefly via video link on Thursday, while Bob Katter is expected later in the day.
The trial continues.