That’s when I saw him—a man in his mid-thirties, shifty-eyed, and overly cautious about his carry-on. He was in seat 16C, and every few minutes, he glanced nervously towards the cockpit. The plane took off smoothly, and once we were at cruising altitude, the cabin lights dimmed. I pretended to read a book but kept my eyes on the man. It wasn’t long before he got up, casually making his way to the restroom.