Complex sentence: Vice President Lyndon B. Johnson was riding in another car 3 cars back, and was sworn in as President aboard Air Force One on the tarmac of Love Field in Dallas shortly after the death of President Kennedy was confirmed.
Split into simpler sentences: Vice President Lyndon B. Johnson was riding in another car 3 cars back. The new President was sworn in aboard Air Force One on the tarmac of Love Field in Dallas shortly after the death of President Kennedy was confirmed.