Berson is largely known for his scientific hot-air balloon expeditions. On 4 December 1894, he ascended to a German record altitude of 9,155 meters aboard the hydrogen balloon Phoenix. On 10 January 1901, with artillery officer Alfred Hildebrandt (1870–1949), he travelled from Berlin to Markaryd, Sweden in a balloon, thus being the first to cross the Baltic Sea by air. On 10 January 1902, with balloonist Hermann Elias (1876–1955), he set the German long-distance ballooning record, as the two men journeyed from Berlin to Poltava in the central Ukraine (1,470 kilometers in 30 hours).