Historical clue formulations

• 24/7 — 2024-08-06
• Desirable flight option — 2023-04-30
• Continuously — 2022-03-28
• Perpetual — 2022-03-16
• On and on and on — 2021-04-15
• All day every day — 2009-03-11
• Direct — 2007-11-30
• Perpetual — 2007-02-13
• 24-hour — 2004-05-04
• Straight through — 2003-04-12
• Incessantly — 2001-04-22
• 24/7 — 2000-10-24
• 24/7 — 2000-02-05
• Going on and on — 1997-12-12