To celebrate President Reagan's inauguration, the Smithsonian is providing a feast of free concerts this weekend at two of its museums -- Air and Space, and American History: AIR AND SPACE MUSEUM MILESTONES OF FLIGHT GALLERY

FRIDAY

11 a.m.-noon: U.S. Army Brass Five, brass quintet.

Noon-1:30: Port Authority of the U.S. Navy Band, jazz and popular music.

2-3:30: Ensemble from the U.S. Air Force Band.

3:30-5: Commodores of the U.S. Navy Band, big-band jazz.

5-6:30: Alan Hauser Quintet, jazz.

6:45-8:45: Tom Cunningham WRC 980 Orchestra; the public is invited to dance.

SATURDAY

11 a.m.-1 p.m.: Hot Mustard Jazz Band.

1-2:30: U.S. Coast Guard Band with the Icebreakers women's chorus, popular music.

3-5: Pikesvill Rye, country and western band; the public is invited to dance.

5-6:30: Country Current of the U.S. Navy Band, country and bluegrass.

6:30-8:30: Johnson Mountain Boys with Hazel Dickens, bluegrass.

SUNDAY

11 a.m.-1 p.m.: Al Webber and the New Memphis Five, early jazz.

1-3: Red Clay Ramblers, Appalachian string band.

3-5: Black American gospel music, soloists, quartets and choirs.

5-7: Buck Hill Quintet, jazz.

7-9: Virginia Commonwealth University Jazz Band, big-band jazz; the public is invited to dance. MUSEUM OF AMERICAN HISTORY CARMICHAEL AUDITORIUM

FRIDAY

Noon-1:30 p.m.: John Eaton, solo piano, jazz and pop.

1:30-3:30: Chamber music performed on 18th-century instruments.

4-5: John Edward Hasse, solo piano, "Ragtime and All That Jazz," illustrated with historical slides.

6-6:30: "Sprout Wings and Fly," a documentary film on Appalachian fiddler Tommy Jarrell.

SATURDAY

Noon-1 p.m.: Chamber music performed on 18th-century instruments.

1-1:30: "Sprout Wings and Fly."

2-3:30: Ronnie Wells and quintet, jazz and American popular songs.

3:30-4: "Sprout Wings and Fly."

4-5:30: Cindy Hutchins, Jody Dall'Armi and Howard Breitbart, vocalists, American popular songs.

SUNDAY

Noon-2: Chamber music performed on 18th-century instruments.

2-3: Koto Society of Washington, Japanese koto music.

3-4: Vocalist Lisa Rich, American popular music.

4-5:30: West End Dinner Theater Company, vocalists with piano accompaniment, selections from musicals.

MONDAY

Noon-1 p.m.: Chamber music performed on 18th-century instruments.

1-2: Musikanten, madrigal singers.

2-3: Takoma Brass Quintet, classical music.

3-4: Linn Barnes and Allison Hampton, lutists.

4-5:30: Steve Jordan, Wally Garner and Van Perry, jazz. MUSEUM OF AMERICAN HISTORY

HALL OF MUSICAL INSTRUMENTS

SUNDAY

3-4:30 p.m.: Smithsonian Chamber Players, "Music for the President," a preview of the music to be performed for the inaugural luncheon at the Capitol. Music for violin, flute, cello, fiddle and hammer dulcimer. MUSEUM OF AMERICAN HISTORY

PENDULUM AREA

FRIDAY

Noon-1 p.m.: Armenian Folk Ensemble of Washington.

1-2: Keter Betts Trio, jazz.

2-3:30: Duke Ellington School Jazz Ensemble.

3:30-5: Celtic Thunder, traditional Irish music.

5-6: Clyde Davenport, Alice Gerrard and Andy Cahan, Appalachian string band.

6:30-8:45: Ralph Case and cloggers, square dance; the public is invited to dance.

SATURDAY

Noon-1 p.m.: Clyde Davenport, Alice Gerrard and Andy Cahan, Appalachian string band.

1-2: City of Alexandria Pipe Band, traditional Scottish music and dance.

2-3: Clyde Davenport, Alice Gerrard and Andy Cahan, Appalachian string band.

3-4:30: Sonny Forrest Quartet, rhythm and blues; the public is invited to dance.

4:30-5:30: George Botts Trio, 1950s rhythm and blues; the public is invited to dance.

5:30-7: The Chasers with Luci Murphy and Charlie Sayles, blues; the public is invited to dance.

7-9: Guitar Bill Harris Blues Band with Charlie Sayles; the public is invited to dance.

SUNDAY

Noon-1 p.m.: Tung-Hsin Choral Society, traditional Chinese music.

1-2: Trinidad Steel Band, traditional steel band music.

2-3: The Chasers with Luci Murphy and Charlie Sayles, blues; the public is invited to dance.

3:30-5: Alan Oresky Klezmer Band, traditional East European and Jewish music.

5-6:30: Los Magnificos, Latin American music; the public is invited to dance.

MONDAY

Noon-1 p.m.: Alexandria Choral Society.

1-2: Alexandria Harmonizers, barbershop quartets.

2-3: Clarinet Connection, jazz.

3-4: Century Brass, 19th-century music.

4-5: John and James Jackson, country blues.

5-6:30: Double Decker String Band, Appalachian string band.

6:30-8:45: Irish Tradition and O'Neill-James Dancers, traditional Irish string band music with step dancing.