President Carter will reimburse the National Bank of Georgia - from both campaign and personal funds - for the cost of five flights Carter took in 1975 and 1976 on NBG's corporate airplane, White House press secretary Jody Powell said yesterday.

The total cost of the flights was $1,793. At least $865 of that amount will be reimbursed from Carter campaign funds, and the remainder from the president's personal funds, Powell said.

Questions about Carter's use of the NBG plane arose in connection with the comptroller of the currency's investigation into the personal financial dealings of budget director Bert Lance.

Lance was asked at a press conference last week whether Carter had ever used the plane. He replied that since use of the plane was still being investigated, it would be inappropriate for him to comment.

However, Powell later said that bank records showed five flights by Carter on the plane. He said officials were checking to determine whether the flights were for campaign purposes and, if so, whether the bank was reimbursed for use of the plane.

The federal election law requires such a reimbursement for campaign flights on private aircraft.

Yesterday, Powell said the records show that two flights - in October, 1975, and December, 1975 - were for campaign purposes. The $644 cost of these flights will be reimbursed from campaign funds, he said. In addition, a third flight, in August, 1975, was partially for campaign purposes. Reimbursement for its $490 cost will come partially from campaign funds and partially from personal funds, Powell said.

The President's other two flights on the NBG plane occured in June, 1976, between Americus, Ga, and Sea Island Ga. Powell said the White House has asked the Federal Election Commission to determine how much of the $659 total cost of those flights should be reimbursed from personal funds.

Earlier, the FEC gave the Carter campaign permission to retain $25,000 in public campaign funds to handle just such situations, Powell said.

The press secretary said the fact that none of the flights were reimbursed initially was an oversight, and not a deliberate attempt to circumvent the election law. But he was unable to explain how Carter came to take the five flights on the corporate plane, and brushed aside as "off the wall conclusions" suggestions that the bank never intended to be reimbursed and offered the plane to Carter because of his close friendship with Lance.