when the balloon goes up —(coll.) when matters become very serious or critical:
- The international rules of war are apt to be waived when the balloon goes up.
when the eagle flies—(U.S. sl.) on payday:
- I’ll pay you back when the eagle flies.
Cf.: eagle has landed, the—(U.S. sl.) paychecks are in:
- The principal got on the PA [public address system] and said, “Teachers, may I have your attention please: The eagle has landed.”