Long lines at the airport and a runway crash this week have been a reminder of how the country’s busiest airports are stretched thin. It all comes a year after a collision between American Airlines flight 5342 and an Army helicopter near Washington, D.C. marked the deadliest aviation disaster in almost a quarter century. Correspondent Sharyn Alfonsi speaks with an air traffic controller inside the tower on the day of the collision and reports on what went wrong and what needs to change. How has Ukraine been able to level the battlefield in the war against Russia? By using remotely controlled and unmanned drones, including on land and sea, against the invading Russian troops. CBS News’ Holly Williams reports the U.S. military is now learning from Ukraine's innovative, battle-tested drone expertise. 

60 MINUTES explores an epic underworld of caverns the size of skyscrapers, known as Hang Son Doong in Vietnam, over a multi-day expedition. The journey reveals a colossal subterranean world: rivers, limestone rock, dense jungle and an underground lake. Correspondent Scott Pelley speaks with the cavers who discovered and surveyed the cave in 2009.