What was going on when I was born?

The air collision over New Jersey Sunday night came after 10 years of increasing traffic by corporate aircraft that has come close to saturating the airspace over New York and its suburbs. Aviation experts say the use of corporate jets, propellor-driven craft and helicopters has changed the way thousands of top executives conduct their business. More than 60,000 corporate planes are now based at airports around the country, each of them lending support to the corporate credo that time is money. While no one has counted the number of corporate planes based in the New York metropolitan area or traveling here each day, the experts say the area has some of the world's heaviest corporate aircraft traffic.

For the first year and a half after the breakup of the Bell System on Jan. 1, 1984, the seven new regional phone companies seemed more alike than different. Now, one of the seven, the Southwestern Bell Corporation, has distinguished itself - and not for flattering reasons. The company, serving a five-state region from its St. Louis base, is not performing so well as the others, some Wall Street analysts say. Since the breakup, they note, revenues in Southwestern's core telephone business have been growing more slowly than those of its peers. Its expenses are burgeoning when the other Bell companies have instituted austerity. As a result, Southwestern Bell's earnings have shown only modest increases this year - including a third-quarter gain of just eight-tenths of 1 percent - while profits at the other regionals have increased sharply. The company's results ''are just not coming in strongly,'' said Eileen Polsky, an analyst at Drexel Burnham Lambert Inc.

Interest rates on Treasury securities continued their descent yesterday, with long-term bond yields moving close to 10 percent, a level not seen since mid-1980. A lack of supply in the Treasury market, hopes that the Federal Reserve will soon ease its monetary policy and the prospects for Congressional action to reduce Federal budget deficits were all cited by analysts as reasons for the decline in note and bond yields. Although many market participants doubt that those three reasons justify continued declines in interest rates, their skepticism did not discourage investors or prevent the price of the bellwether 10 5/8 percent Treasury bond due in 2015 from gaining more than 7/8 point on the day, to an offered price of 105 18/32, to yield 10.03 percent. The closely watched 30-year issue traded as high as about 105 25/32 to yield 10.01 percent - a far cry from the Oct. 28 close of 101 to yield 10.51 percent.

Lloyd's of London, in concluding its investigation into a series of scandals that came to light in 1982, today imposed a record $1.4 million fine and expelled from its membership the former head of an insurance syndicate who diverted $60 million in insurance funds to himself and a small group of associates. In its action, the insurance underwriting exchange described Peter S. Dixon, former head of PCW Underwriting Agencies, as ''a clever, dishonest, greedy and unscrupulous individual.'' Lloyd's added that Mr. Dixon's shady practices over a period of more than a decade ending in 1982 were ''a complete negation'' of the principles of honesty and integrity that are the foundation of the nearly 300-year-old insurance exchange. ''The PCW case was the most significant of the troubles'' at Lloyd's in recent years, said Peter Hill, a Lloyd's spokesman. ''And this is the last of them to be dealt with.''

Markets The stock market rally showed signs of spreading to more secondary issues after its recent blue-chip run-up. The Dow Jones industrial average rose 1.72, to 1,433.60. Broader-based market indicators had good gains and trading was heavy. [Page D1.] Yields on Treasury securities continued to fall amid a shortage of supply, hopes for a relaxed Fed policy and Congressional efforts to reduce Federal budget deficits. [D1.] Treasury bond futures soared to their highest level in five years. [D18.]

Some visitors call them keepers of the flame. Durango Mendoza calls them ''Rambos for peace'' - the tiny paid staff and pool of 150 volunteers and 1,500 donors who lovingly built and now sustain the four-year-old Peace Museum here. Mr. Mendoza, a social worker with the Illinois Department of Children and Family Services, says he retains a strong interest in peace issues, but he also confesses that the concept of a peace museum initially struck him as odd. ''My first thought was 'What's in it?' '' said Mr. Mendoza, who was visiting the museum with his wife, Jean, and three of their four children. ''There are always enough artifacts of war, but how do you keep a peace museum going?''

International Democratic strategy for the summit meeting next week is in place, according to party officials in the House. They said Speaker Thomas P. O'Neill Jr. planned to say today he had high hopes for the meeting. The statement is reportedly part of an effort to place the responsibility squarely on President Reagan in the event the meeting is seen to fail and, alternatively, to help blunt the effect on Democrats of a successful meeting. [Page A1, Column 6.] Eliminating U.S.-Soviet distrust is Washington's primary objective in the summit meeting next week, President Reagan said. [A10:1.]

Hovering over preparations for the Soviet-American summit meeting, as over any high-level East-West contact these days, is the plight of thousands of people who have clashed with the Government or simply want to leave the Soviet Union. This human rights issue is one that Mikhail S. Gorbachev has confronted in London, in Paris and in his meetings here with Western officials, and it is one that President Reagan has said he will raise in the Geneva meeting a week from now. For the dissidents, divided spouses, relatives of political prisoners, religious sectarians, nationalists and others who have come into conflict with the authorities, the issue is hardly abstract. Once again, fading hopes and yellowing appeals are being revived.

Frank Alfredo never dreamed he would become a landlord. But then Mr. Alfredo, a landscape architect from Westchester County, was offered what seemed like an unbeatable deal on two cooperative apartments in Manhattan. There was one catch: The apartments were not vacant. They came with tenants. He bought them anyway, and became a player in one of the city's latest high-stakes, high-risk, real-estate poker games - the purchase of occupied cooperatives or condominiums made available by the conversion of apartment buildings under noneviction plans. Mr. Alfredo bought his apartments - a studio and a one-bedroom in the Gramercy Park neighborhood - for $120,000, about $80,000 less than they would have cost vacant. ''I see people making money so easy in real estate,'' he said. ''I say, 'Why can't I do it?' ''

Stock prices, after dashing upward on Monday, moved further into record territory yesterday, and the rally showed signs of spreading to more secondary issues. The session was the seventh busiest in the market's history. ''Everything considered, the market put on a good show,'' said Alfred Goldman, a market analyst for A. G. Edwards Inc. The Dow Jones industrial average has led the market higher for the last two weeks, culminating in a 27.52-point rise on Monday. Yesterday the blue-chip index rose further, with a 1.72-point gain, to 1,433.60.

''There is a crying need for babies,'' Sabena Basch said yesterday with no trace of a smile. She is co-owner of the Li'l Stars Talent and Modeling Management Agency, whose office was - ''Don't step on the baby!'' - filled with babies yesterday: black babies, white babies and Hispanic babies, laughing, gurgling and screaming bloody murder. As Mrs. Basch and her partner, Adelle Sharf, tried to do business, the babies tipped over containers of pens and pushed buttons on the phones, disconnecting callers. The people would call back and say, ''Don't push the button, honey, don't. . . .'' The babies were - ''Eric! Don't pull her hair!'' -getting into everything. Marilyn is into residuals. The 19-month-old, who still receives checks for a Fisher-Price toy advertisement, was wearing a T-shirt reading ''Kid for Rent.''

Arthur James Walker was sentenced today to life in prison and prosecutors raised the possibility that his espionage activities had been more serious than previously charged. Prosecutors said that some evidence gathered by the Government indicated that Mr. Walker, a retired Navy lieutenant commander, might have started spying while still in the military. They also said he might have recruited his brother John A. Walker Jr. into espionage, rather than the other way around. Previous Accounts Contradicted That would contradict previous accounts by law-enforcement officials who had said John Walker, another Navy veteran, had formed the espionage operation, described as one of the most damaging in American history. According to most accounts, John Walker, who has pleaded guilty, became a spy in the mid-1960's and recruited his brother and son a decade later.