Question: English conductor Dale Clevenger was a member of Leopold Stokowski's American Symphony Orchestra and the Symphony of the Air directed by who?
Context: Ainslee Cox (1936, Big Spring, Texas – September 5, 1988, New York City) was an American conductor.  A graduate of Westminster Choir College and the University of Texas at Austin, he was associate conductor of the American Symphony Orchestra in 1962 under Leopold Stokowski and later an assistant conductor of the New York Philharmonic under both Leonard Bernstein and Pierre Boulez. The American Symphony Orchestra is a New York-based American orchestra founded in 1962 by Leopold Stokowski whose mission is to demystify orchestral music and make it accessible and affordable for all audiences.  Leon Botstein is the orchestra's music director and principal conductor.  They perform regularly at Carnegie Hall and Symphony Space in New York City, and are also the resident orchestra of the Richard B. Fisher Center for the Performing Arts at Bard College, Annandale-on-Hudson.  Its concertmaster is Erica Kiesewetter. The RCA Victor Symphony Orchestra, sometimes also known as the RCA Victor Salon Orchestra, the RCA Victor Orchestra and simply, the RCA Orchestra was an American studio orchestra founded in 1940 by the RCA Victor record label for the purposes of making recordings.  Originally established as a salon orchestra based at RCA Victor headquarters in Camden, New Jersey, the group was created by Victor staff conductor Nathaniel Shilkret.  The name later was used for free-lance orchestras, mainly in New York City, assembled as needed to make recordings for RCA Victor through the early 1960s.  Its players included those from the New York Philharmonic, the Metropolitan Opera, the NBC Symphony Orchestra, and other major ensembles.  The RCA Victor Orchestra recorded with notable conductors including Leopold Stokowski, Fritz Reiner and Leonard Bernstein.  A number of their recordings received Grammy Awards.  In the early 1960s the orchestra was disbanded when RCA moved much of its recording activity to Europe and established the RCA Italiana Orchestra at its studios in Rome. George Lynn (1915 – March 16, 1989) was an American composer, conductor, pianist, organist, singer, and music educator.  A longtime member of the American Society of Composers, Authors and Publishers, his compositional output encompasses more than 200 orchestral and choral pieces; many of which have been performed by major American symphony orchestras like the Denver Symphony, the American Symphony Orchestra under Leopold Stokowski, and the Philadelphia Orchestra.  He taught on the music faculties of several prominent American colleges, notably conducting several university choirs.  Throughout his life he was active as a conductor, organist, and pianist for various church and community choirs. Symphony No. 2, Op. 132, Mysterious Mountain is a three-movement orchestral composition by the American composer Alan Hovhaness.  The symphony was commissioned by the conductor Leopold Stokowski and the Houston Symphony, and premiered live on NBC television in October 1955 on the Houston Symphony's first program with Stokowski as conductor.  A popular recording of the work, released in 1958 with the Chicago Symphony Orchestra performing under Fritz Reiner, is often regarded as the foremost performance of the piece. Albert Tipton (March 16, 1917 – October 5, 1997) was an American flutist, pianist and conductor.  In 1966, "Time" placed Albert Tipton amongst the "30 first-rate flutists" in the United States and Europe.  He studied with William Kincaid at the Curtis Institute of Music in Philadelphia.  He served as principal flutist with the National Symphony Orchestra from 1937 to 1939 and toured with Leopold Stokowski as a soloist with the All American Youth Orchestra in 1939.  He became second flutist with the Philadelphia Orchestra in 1940 and left that position in 1946 to become the principal flutist of the St. Louis Symphony Orchestra (1946–1956).  He was in Detroit from 1956–1968, where he played principal flute in the Detroit Symphony Orchestra.  In 1968 he accepted a position at Florida State University as Professor of Flute.  He later moved to Rice University in Houston, Texas serving as Professor of Flute from 1975 to 1990. Adam Schoenberg (born November 15, 1980) is one of the most performed living American composers.  A member of the Atlanta School of Composers, his works have been performed by the Amarillo Symphony, Atlanta Symphony Orchestra, Buffalo Philharmonic Orchestra, Charleston Symphony Orchestra, Charlotte Symphony Orchestra, The Cleveland Orchestra, Dallas Symphony Orchestra, The Florida Orchestra, Fort Worth Symphony Orchestra, Grand Rapids Symphony, Jacksonville Symphony, Kansas City Symphony, Knoxville Symphony Orchestra, Lake Forest Symphony Orchestra, Lexington Philharmonic, Los Angeles Philharmonic, National Symphony Orchestra, New West Symphony, New World Symphony (orchestra), New York Philharmonic, Orlando Philharmonic Orchestra, Pacific Symphony, Phoenix Symphony, Rochester Philharmonic Orchestra, San Diego Symphony, South Carolina Philharmonic, Tallahassee Symphony Orchestra, Waterloo-Cedar Falls Symphony, among other ensembles.  Schoenberg was the 2010-2012 guest composer for the Aspen Music Festival, the 2012-2013 composer-in-residence for the Kansas City Symphony, the 2013-2014 composer-in-residence for the Lexington Philharmonic, and the 2015-2017 composer-in-residence for the Fort Worth Symphony.  Schoenberg's honors include a 2009 and 2010 MacDowell Colony fellowship, the 2007 Morton Gould Young Composer Award from ASCAP, and the 2006 Charles Ives Prize from the American Academy of Arts & Letters. Dale Clevenger (born 1940 in Chattanooga, Tennessee) was the Principal Horn of the Chicago Symphony Orchestra from 1966 until his retirement in June, 2013.  Before joining the CSO, he was a member of Leopold Stokowski's American Symphony Orchestra and the Symphony of the Air directed by Alfred Wallenstein.  He was also principal horn of the Kansas City Philharmonic.  He currently teaches at theJacobs School of Music in Indiana University. The NBC Symphony Orchestra was a radio orchestra established by David Sarnoff, the president of the Radio Corporation of America, especially for the celebrated conductor Arturo Toscanini.  The NBC Symphony performed weekly radio concert broadcasts with Toscanini and other conductors and served as house orchestra for the NBC network.  The orchestra's first broadcast was on November 13, 1937 and it continued until disbanded in 1954.  A new ensemble, independent of the network, called the "'Symphony of the Air'" followed.  It was made up of former members of the NBC Symphony Orchestra and performed from 1954 to 1963, notably under Leopold Stokowski. Leopold Anthony Stokowski (18 April 188213 September 1977) was an English conductor of Jewish-Polish and Irish descent.  One of the leading and influential conductors of the early and mid-20th Century, he is best known for his long association with the Philadelphia Orchestra and for appearing in the film "Fantasia".  He was especially noted for his free-hand conducting style that spurned the traditional baton and for obtaining a characteristically sumptuous sound from the orchestras he directed.
Answer: Alfred Wallenstein