Times of crisis often reveal the character of leaders. At Yahoo Finance's Invest 2025 event, Pfizer (PFE) CEO Albert Bourla and Delta Air Lines (DAL) CEO Ed Bastian shared how their values have guided their decisions in turbulent times. "I'm very optimistic," said Bourla, who goes with a "nothing is impossible" mindset. "If there is something about me as a leader ... it is my optimism." Bourla, whose tenure at Pfizer spans over 25 years, has led the drugmaker through the COVID-19 pandemic. He attributes ...