Former Prime Minister Ehud Olmert said during his corruption trial Thursday that he paid for flight upgrades and tickets for family members using either points or his personal credit card.

"We paid for flight upgrades and tickets for family members using frequent flier points, and otherwise using my personal credit card," Olmert said during his testimony at Jerusalem District Court.

During the former prime minister's corruption trial, he is expected to respond to the three main charges against him: double-billing nonprofits for the same overseas flights and using the surplus to fund personal vacations, receiving cash-filled envelopes from American Jewish businessman Morris Talansky, and improperly interfering in decisions at the Industry Ministry's Investment Center. Most of the alleged offenses occurred while he was either industry minister or finance minister.

Olmert addressed the charges regarding double-billing his flights while in court on Monday.

"I did not even specifically know the exact accumulation, said Olmert on the witness stand, "I did not know the number. I travelled countless times over the years."

"I knew that I had numerous points with numerous companies… I did not deal with all the details of that combination," Olmert said, adding that he was not familiar with the method of accumulating and using points.

"I assumed that the more you fly, and the more you fly in first or business class, the larger the accumulation and bonuses, and that totaled knowledge of the matter. Anything beyond that was like all technical aspects of flying."

Olmert said he left his credit card details with his travel planner, Rachael Risby-Raz, and had an arrangement with her that should he not have sufficient points for any upgrades or family member flights, she would pay for them with his personal finances. He added that Risby-Raz never contacted him on the matter, and thus he did not know how many flights were paid for using points or his personal finances.

Among the issues that Olmert is expected to be asked about during his trail is testimony by his good friend, attorney Uri Messer, who said he kept hundreds of thousands of shekels in cash for Olmert at a safe in his office, and by his travel planner, Rachael Risby-Raz, who said Olmert was fully aware of the double-billing.