LOS ANGELES (AP) _ Jazz singer Ella Fitzgerald has been improving daily since undergoing open heart surgery and soon will leave the intensive care unit, a hospital spokesman said Saturday.

''Her recovery has been very normal,'' Cedars-Sinai Medical Center spokesman Ron Wise said.

Miss Fitzgerald, 68, was listed in stable condition at Cedars-Sinai, where she underwent a coronary bypass Wednesday after being admitted Aug. 19, Wise said.

''She probably will be transferred sometime this weekend into a private room, where she'll probably be for about a week while she starts walking around and getting her strength back,'' Wise said.

A spokeswoman for Miss Fitzgerald said the singer's concert engagements for the remainder of 1986 have been canceled.

Miss Fitzgerald was hospitalized with congestive heart failure after becoming ill in her hotel room following a July 26 performance in Lewiston, N.Y.

Known for her improvisational ''scat'' singing, Miss Fitzgerald has made more than 250 record albums, and her biggest hit, ''A-Tisket, A-Tasket,'' which she co-wrote, has been enshrined in the Grammy Hall of Fame.

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PHILADELPHIA (AP) - Comedian David Brenner will headline a program of distinguished alumni when West Philadelphia High School celebrates its 75th anniversary next year.

Joseph Pollock, former superintendent of schools in Scranton, Pa., and president of the alumni association, said all living retired teachers who were on the West Philadelphia faculty will be guests at the reunion.

''We hope to reach more than 50,000 alumni now living all over the United States and the world,'' Pollock said.

Among prominent alumni are show business stars Jeanette MacDonald, Gale Sondergaard, Paul Douglas, John Carradine, ''My Fair Lady'' producer Herman Levin and pianist Eugene List.

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NEW YORK (AP) - Jane Pauley, new mother and ''Today'' show host, will stay up late Thursday for a brief appearance on the morning program's live prime- time special, ''Today At Night, Volume II.''

Pauley, who gave birth to her third child, Thomas Moore, Aug. 27, has been on maternity leave since late July. Her husband is ''Doonesbury'' comic strip artist Garry Trudeau.

She is scheduled to return to NBC's top-rated morning broadcast on Oct. 10, the day before her 10th anniversary on ''Today.''

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LONDON (AP) - American balloonist Vera Simons says she has received offers from other European cities to do a sky sculpture for them, after putting an ''aerial crown'' on the National Gallery of Scotland for three weeks.

Her two-thirds size replica of the neoclassical building in white balloon fabric was inflated on the roof during the three-week Edinburgh International Arts Festival last month.

By day, the sculpture, which was 100 feet long, 66 feet wide and 28 feet high, reflected the changing sky. By night, it was illuminated.

Other cities showing interest are in Scotland, England and continental Europe, Miss Simons said before leaving Saturday for her home in Washington, D.C.

Miss Simons, who now spends more time as an artist than as a balloonist, holds an unofficial women's world record of 133 hours continuously aloft in a balloon.