Complex sentence: For at least the first quarter of a century on-the-air, WAGT aired virtually no local newscasts apart from brief news and weather cut-ins during "Today" on weekday mornings.
Split into simpler sentences: For at least its first quarter of a century on the air, WAGT aired virtually no local news, apart from cut-ins during Today. Before this, it had virtually no local news aside from cut-ins during "Today" on weekday mornings.