Northwest Orient Flight 370 delivered Sen. Richard G. Lugar (R-Ind.) to Minneapolis at 10:19 a.m. Jan. 11. He went to give speeches, but took with him no prepared texts.

At noon he addressed the employes of Pillsbury, among them the political action committee of the firm. Fee: $1,000.

At dinner he spoke to executives and board members of First Bank Systems, a bank holding company. Fee: $2,000.

The next morning he spoke to executives and board members of the Fingerhut Corp., a mail-order firm. Fee: $2,000.

Then he spoke at a luncheon sponsored by Miller and Schroeder Municipals Inc., a financial firm. Fee: $2,000.

After lunch he addressed senior executives of General Mills at their headquarters. Fee: $1,500.

In a period of about 30 hours, Lugar had received $8,500 in speaking fees.

Until five months ago U.S. senators had a self-imposed restriction against earning more than $25,000 a year for speeches. Congress voted to eliminate that ceiling, and today Lugar is one of a number of senators for whom the change has meant thousands of dollars in extra income, and could mean thousands more.

Limitations on income from speeches were imposed as part of post-Watergate ethical reforms in the 1970s. The $25,000 limit was removed as many senators complained that inflation was eroding their annual salaries of $60,662.50. Some senators also said the limit was unfair.

"I'm well aware there is a public feeling that our salary is about where it ought to be," Lugar said recently. "But it seems to me that those of us who want to make additional income in recorded ways ought to be free to do so."

Interviews with more than 50 senators or members of their staffs show that many agree with Lugar. Several senators went over the old $25,000 limit right after the ceiling was eliminated.

For example, Charles McC. Mathias Jr. (R-Md.) earned an additional $15,000 in the last three months of the year, bringing his total for 1981 to $40,300 in speaking fees--two-thirds of his congressional salary. Paul Laxalt (R-Nev.) collected $8,500 in speaking fees, supplementing the $25,000 he earned before the limit was lifted. Orrin G. Hatch (R-Utah) gave speeches totaling $15,850 in fees after the limit was removed. James A. McClure (R-Idaho) added $6,850 for speaking.

It is not uncommon for senators to give several speeches in one day, although senators are still limited to receiving no more than $2,000 per speech. In 1980 one-third of the Senate collected more than $20,000 in speaking fees.

"I do think this is a subject that is so easily misunderstood," Mathias said. "It is very difficult for people whose salaries are a fraction of the congressional salaries to understand the kind of financial pressure that can exist."

Still, other senators said that lifting the $25,000 ceiling was wrong.

"We have cut spending for education of poor children . . . for health programs . . . for nutrition programs," said William Proxmire (D-Wis.), who led the Senate floor fight to retain the limit.

He said the Senate should not turn around and allow its members to earn $50,000 to $100,000 for speeches while asking the public to make financial sacrifices.

The question of honoraria, or fees, for speeches cuts across party lines, and is viewed somewhat differently by almost every senator. More than three-quarters of those in the Senate accept fees for speeches.

Some senators say they feel that frequent speaking engagements take valuable time from their jobs in Washington. Others say that accepting money from private corporations or political interest groups can create a serious conflict of interest. Some will not accept money from any group in their home state; still others say there are no ethical problems as long as the senator publicly reports all of his speaking fees.

"Surely it could be the equivalent of a bribe if it were abused," Mathias said. "The guarantee against that is the publication."

Sen. Lawton Chiles (D-Fla.) is one of several millionaires in the Senate who refuse to accept any honoraria for speeches because of potential ethical problems.

"He is concerned about conflict of interest," said Jack Pridgen, an aide to Chiles. "These conflicts undermine public confidence. There is a perception that you can buy a public official."

Sen. John C. Stennis (D-Miss.) also will not accept honoraria. "He views giving speeches as part of his job," said Rex Buffington, an aide to Stennis. "He feels it is not proper to take money for speeches."

Some senators point out that invitations to give speeches are not necessarily due to their speaking abilities. "It is not our talent which gets us invited," said Sen. Rudy Boschwitz (R-Minn.), "but rather the supposed power which comes to us as seniority grows."

Sen. Robert J. Dole (R-Kan.) says that many senators who are not wealthy need the extra money. He says the $25,000 limit was unfair and unnecessary, adding that senators have had no income restrictions regarding publication of books or other outside sources of income.

"I'm not certain there ever should have been a limit on speaking fees ," Dole said. "I remember the old days when Hubert Humphrey used to go out and pile up the money, $70,000, $80,000 . . . . As long as you have to report your honoraria and let the public know, people will make their judgment at election time."

Lugar is not the only senator to collect several thousand dollars in fees during a quick trip to Minneapolis. At least eight other senators in the past two years have made similar trips to Minnesota.

The list of senators who made the trips includes Robert C. Byrd (D-W.Va.), the minority leader, who earned $6,000 for three speeches; Alan Cranston (D-Calif.), who received $5,000 in two days; Mathias, who earned $5,000 in one day; James J. Exon (D-Neb.), who received $4,000 in one day; William V. Roth Jr. (D-Del.), who earned $4,700, as well as Dole, Jake Garn (R-Utah) and George J. Mitchell (D-Maine), whose figures are not yet available.

Most of those senators spoke to several firms whose financial interests could be affected directly by federal legislation or policy. The speeches were set up by Wendell Anderson, an attorney and former Minnesota Democratic senator.

Two of the firms said that Anderson represented them as an attorney, and a third said Anderson was a close friend of the firm's president.

"He represents us in governmental affairs or government relations or whatever you want to call it . . . . I suppose that's just a euphemism for lobbying," said Jim Weiler, a vice president of Miller and Schroeder Municipals Inc.

Anderson, who said he is not a lobbyist, remarked: "I am not embarrassed to say I'm not a big-time Washington lobbyist. I'm just a small-town lawyer delighted to have my friends out here . . . . I'm just trying to be of some modest help to my former colleagues, with whom I shared the same very serious financial problems."

All but one of Lugar's speeches in Minneapolis were set up by Anderson. Lugar said he was unaware that Anderson represented any of the firms. The speeches covered a variety of topics.

Don Pratt, vice president of First Bank Systems said, "Our particular interest in him was, of course, as a member of the Senate Banking Committee."

In speaking to General Mills, Lugar had a note in the margin of his schedule that said: "Grain embargo and the prospects of its reimposition." Lugar has been an opponent of the embargo.

Between his five paid speeches, Lugar spoke for no fee to a university gathering and to Investors Diversified Services Inc., a financial firm. Lugar, who is seeking reelection this year, said he gave the speech to IDS in hopes of receiving campaign contributions.

Lugar said in an interview that he gave the same half-hour speech, followed by questions and answers, to each group. He said he is aware of the potential for conflict of interest, but is said he is confident that the $2,000 limit per speech and public disclosure will prevent such abuse.

"This is a period in my life when the additional income is especially needed," he said. However, he added, "It's not an acute need." He said that with his congressional salary, plus $40,000 from family investments and $25,000 from speeches, he earned about $125,000 last year.

As of Feb. 1 Lugar already had earned $16,300 for speeches in 1982, three times as much as he earns in his congressional salary in one month. He said he does not expect to keep up the fast pace in earning honoraria through the rest of the year. He said the Minneapolis visit came when Senate was out of session and the compact schedule minimized his time away from official business.

He said he also saw professional value to his Minnesota speeches. "During the course of that kaleidoscope of events," he said, "I gained a variety of impressions as to how these business leaders were coping with the economy." In addition, he said, "I enjoy giving speeches."

Mathias said he does not enjoy giving speeches, but said he feels he must to make ends meet.

"He abhors having to go outside and give speeches," said Mathias' aide, Jack Eddinger.

Nonetheless, on Aug. 1, 1980, Mathias accepted an invitation from Anderson to speak to three Minneapolis firms. He collected $5,000 for those three speeches on one day.

One of his speeches to senior executives in the board room of Fingerhut Corp. Mathias discussed interstate tax legislation to make state laws more uniform, according to Eddinger. The mail order firm does much interstate business.

The Senate was in session that day. Mathias was absent and missed a roll-call vote on the appointment of a member of the National Labor Relations Board.

In an interview, Mathias pointed out that he has had a good voting attendance record overall--81 percent in seven years. He also said the meeting at Fingerhut would not influence his actions on the tax legislation, since he has supported the changes for over a decade.

He said he regrets having to earn money from speeches, but that he feels he has no choice. He said he would prefer that the Senate receive a direct cost-of-living adjustment in salary. "We did not do that, so we've been reduced to these alternatives, which are in many ways undesirable but indispensable," Mathias said.

"The whole question of my finances is difficult," he said. "It's really salt in the wound." He said that to put two children through college and meet his other financial demands he needs more than his congressional salary.

That salary, combined with his earnings from speeches, gave Mathias $100,962 in income last year.

"I sometimes kid myself and say I'm a wandering troubadour," Mathias said. "I'm not alone."

A review of disclosure statements for 1980 confirms Mathias' assessment. Records show that in 1980, when the Senate still had a $25,000 limit, 22 senators earned above $24,000, 11 earned over $20,000 and 16 more earned above $10,000.

During the Senate debate on whether to lift the $25,000 ceiling, some senators said that unlimited speaking engagements could affect work adversely in Washington.

Sen. Strom Thurmond (R-S.C.) said, "We are elected to Congress for one purpose: to serve our constituents. Someone who is spending too much time involved in outside speaking engagements . . . cannot give the voters the representation they expect."

In a typical example, Paul E. Tsongas (D-Mass.) spoke in Miami on Feb. 19, 1980, receiving a $1,000 fee. On the same day he missed a hearing in the Senate regarding the Home Mortgage Disclosure Act.

"We make every effort that we not schedule speeches when there are votes or committee hearings, but we don't always hit 100 percent," said Mary Ellen Thompson, an aide to Tsongas. Tsongas hit the $25,000 limit in 1980 and received about as much in 1981, Thompson said.

The 1980 disclosure statements show that senators frequently speak to corporations or interest groups with concerns about pending legislation or government policy.

Sen. Howard W. Cannon (D-Nev.), for example, earned $24,500 in speeches in 1980. The chairman of the aviation subcommittee, Cannon collected fees from groups such as the Airline Pilots Association, the Commuter Airline Association of America, and the National Air Transportation Association.

On May 14, 1980, Cannon addressed the Freight Forwarders Institute on the subject of trucking deregulation. He received $1,000. At the time Cannon had authored a bill to deregulate the industry.

A Cannon aide, Mike Vernetti, said there was nothing improper in accepting money from those groups. He said he sees no "attempt to buy favor . . . . It's a business deal, and has nothing to do with voting the interest of the group."

"Hell, Cannon is as often against them as for them," Vernetti added. He said he did not believe that a senator would change his vote "for a crummy $2,000."