Just a few years ago, the often-troubled SAS was merely inches away from seeing its light burn out permanently. Since then the airline has rallied. This past October the airline completed its best fiscal year in two decades. Is the airline merely surfing the buoyant European economy? Or is it building long-term success? Finnair is also enjoying a brilliant year. Icelandair is coping with growing competition. And the Air Berlin parts sale is largely settled.

In the U.S., Spirit announced that in 2019 it will again part ways with its CEO, which happened just a couple years ago. Frontier had a pretty solid 2017, but it didn’t launch an IPO. Lastly, Delta kicks off earnings season this week.