Donna Casey stepped aboard her Hawaiian Airlines flight to Honolulu and looked for her seat. She splurged for a $4,300 seat in business class and was prepared for 13 hours of lie-flat comfort and cocktails. As she put her carry-on in the overhead bin, she looked down to find a woman comfortably settled in her seat. “I told her nicely, ‘I think you’re in my seat,’ and she just stared at me,” Casey said. “I said it again, and she said, ‘There are plenty of seats in this section, maybe try...

Paul Williams is one of the world’s most influential and respected atmospheric scientists. Through his groundbreaking research, he found that severe clear air turbulence — turbulence that can’t be detected by radar, is invisible to the naked eye, and can be deadly to travelers — has increased more than 55 percent since 1979 due to climate change. So how does Williams, who holds a PhD in physics from Oxford and leads a team of 30 atmospheric scientists, balance his academic knowledge of...