Marek was born in Prague on March 17, 1917, in Prague’s Žižkov district, and first became involved in Scouts there at a troop at the Church of St. Procopius (Prokop). He enlisted as a volunteer in the First Air Force Regiment in 1936, which began a lifelong interest in aviation. He was demobilized in 1939, but he continued to love aviation. He made a tandem jump at age 102.