Perdue served two terms as Lt. Governor beginning in 2000.
There is a provision in the state ethics code that says gifts can be accepted on behalf of the state or for use by the state or for the benefit of the state.
Governor Perdue's office told ABC11 the flights she took as lieutenant governor were gifts to the state and didn't have to be paid for.
But that reasoning is drawing fire from both sides.
"Nobody just gives gifts to the state. They're giving a flight to a very powerful woman for some reason. It may differ upon the individual or entity involved, but they're giving gifts to her," North Carolina Republican Party Chairman Tom Fetzer said Thursday.
"What is there to gain from someone giving a gift of a free flight to a state official?" said Democratic Consultant Brad Crone.
That's what North Carolina government watchdog Frank Perry is concerned about. Not so much the free flights, but what they imply.
"The gift to the state means what? What is the benefit to the individual providing the so-called gift to the state?" he asked.
Another shared concern is the lack of reporting. Only now are some of the flights - and the names of the people who provided them - coming to light.
No one - including those in the governor's office - was able to tell us where, if anywhere, the flights were reported.
"There's no transparency here as to the reason and what the results will be as far as quid pro quo," said Perry.
Comparing detailed lists of flights Perdue took with her expenses as lt. governor suggests no flights taken for state business were paid for in 2007 or 2008. And where flights were shared for campaign purposes, only the campaign portion was paid back.
Perry says it's a slippery slope.
"If we hide behind this claim of gifts to the state, we have some serious transparency issues," he said.
Perdue's staff said Thursday that the benefit to the state for taking the flights was a saving to taxpayers.