Complex sentence: He continued to fly for NWA and in 1938 made news once again, this time by successfully making a high altitude flight from St. Paul to Billings and then on to Salt Lake City using a newly designed oxygen nose mask.
Split into simpler sentences: He continued to fly for NWA and in 1938 made news once again. This time by successfully making a high altitude flight from St. Paul to Billings and then on to Salt Lake City using a newly designed oxygen nose mask.