The scene at Chicago's O'Hare Airport Wednesday suggested the arrival of a movie star or high political figure. Swarms of reporters, TV crews and waiting crowds burst into applause as the smiling man in a black suit emerged from the flight from Cincinnati.

The focus of all this attention was not a hot Hollywood property, but Archbishop Joseph L. Bernardin, up for a quick visit to the city where he will be formally installed as the Roman Catholic archbishop on Aug. 25.

Few men have approached a new job bearing the hopes of so many people. For 16 years, the Chicago archdiocese, once the pride of Roman Catholicism in this country, has been all but paralyzed by a devastating war between an autocratic prelate, the late Cardinal John P. Cody, and priests and lay members seeking to put into practice in Chicago the reforms outlined nearly 20 years ago by the Second Vatican Council.

Chicago Catholics are euphoric about Cody's successor, for Bernardin, 54, is widely seen as a strong supporter of the Vatican II church and its philosophy of openness and shared responsibility.

" . . . A man of compassion . . . a man of prayer . . . a man who can listen . . . . I expect strong committed leadership from him," said Msgr. John J. Egan, assistant to the president of the University of Notre Dame.

" . . . An outstanding churchman, a person of deep personal sensitivity . . . a great blessing for the archdiocese," said the Rev. James Roache, a former communications secretary of the Chicago archdiocese.

" . . . The kind of man who can help put this diocese back together again," said Ed Marciniak, a nationally known lay leader.

" . . . Great for the spirit of Chicago," said Mayor Jane Byrne. "We now have the best of all worlds."

Bernardin is aware of the expectations of his new flock. Their overwhelming response, he said in a telephone interview, "is a source of great satisfaction to me. I go there willing and anxious to love the people and work with them and know them and share my insights with them so that together we may love the Lord.

"At the same time," he added, "I'm enough of a realist to know that it's not going to be easy."

For starters, the 2.4 million-member Chicago archdiocese, the largest and richest in the United States, is roughly five times the size of the Cincinnati archdiocese. But Bernardin is universally given high marks for his administrative skills.

Chicago's biggest problem, the bitterness of the long-running battle between prelate and priests--especially the younger activists--has been all but wiped out by Cody's death and Bernardin's reputation for openness and conciliation.

Also, the threat of financial scandal over allegations that Cody had used church funds improperly was removed when the U.S. attorney's office abandoned its investigation after Cody's death.

But other problems remain. Foremost among them is personnel. This year, when the archdiocese graduated only seven seminarians into the priesthood, 30 experienced priests reached the mandatory retirement age of 70. The church faces an acute shortage of priests within a very short time.

There are only two auxiliary bishops in Chicago, and one of them is virtually incapacitated by illness. By contrast, New York, with only three-fourths the number of Catholics, has seven. While Bernardin will be hampered initially by lack of help, he has promised to remedy the situation, choosing some new auxiliaries from the ranks of black and Hispanic Catholics. One candidate is said to be the Rev. Edward K. Braxton, a Chicago priest who is currently serving as theological adviser to Washington Archbishop James A. Hickey.

By selecting Bernardin for the archdiocese, Pope John Paul has done more than merely fill a vacancy. He has signaled that the vision of a renewed and updated church that emerged from the Second Vatican Council is now the norm for Catholicism in this country.

Egan sees in the Bernardin appointment a clear message to right-wing Catholics who have opposed many of the Vatican II reforms. "The pope is really saying to them: 'Shape up and join the church,' " Egan said.

Bernardin has had a role in shaping the church in the United States ever since 1966 when he was plucked from the remote post of an auxiliary bishop in Atlanta to become general secretary of the newly formed National Conference of Catholic Bishops and its service arm, the United States Catholic Conference.

In Catholicism, every bishop is autonomous within his own diocese. But through the national bishops' conference--itself a concept proposed by Vatican II--they cooperate in a variety of matters ranging from doctrine to social action, from ecumenism to legislative action.

Even after his appointment in 1972 as archbishop of Cincinnati, Bernardin became a sort of gray eminence in conference affairs. He maintained almost daily telephone contact with conference offices here, both before and after his 1974-77 term as president of the conference, sometimes to the chagrin of his successor as general secretary.

Though he is generally described as a progressive on social issues, he is not expected to deviate from traditional Catholic positions. He drew sharp criticism from some liberal Catholics in 1976 following the national grass-roots Call to Action conference when he quickly distanced himself from conference positions that differed from Catholic tradition, such as opening the priesthood to women and married men.

Urbane and approachable, he is vastly more likely to be referred to by his associates as "Joe" than as "his eminence." He meets people easily and on Monday he stunned visiting Chicago reporters, accustomed to the inaccessibility of his predecessor, by inviting them to an informal picture-taking session in the three-room Cincinnati apartment where he has lived since selling the traditional archbishop's mansion.

A self-confessed workaholic, Bernardin is hard-pressed to answer a question about what he does for recreation. "For exercise, I walk every evening," he finally said.

Bernardin spends "a great deal of time in evenings and weekends"--assuming he isn't preaching or speaking somewhere--"doing my writing, and to be able to write, you have to read," he said. He subscribes to "20 or 25 periodicals," he said, secular as well as religious. "Then I try to keep up with the books that are being written . . . . So I turn on my record player, to a symphony or opera, and read."

Asked about his priorities for his new assignment, Bernardin said, "I'm not going with a check list of things that need to be done . . . Any new planning needs to be done after study and consultation with the people there.

"Basically," he said, "I want to be a good pastor."

He is losing no time in demonstrating his people-oriented style to his new flock. After his formal installation at Holy Name Cathedral next month, which he has specified must be "simple and joyful," he would like to have a big, festive outdoor mass and picnic in Grant Park the following Sunday.

He wants to start off, he said, with "something to which I can invite everyone."