Related Clues:

• Greek "H"
• Passengers' datum, briefly
• Key on a keyboard
• Posting at O'Hare: Abbr.
• Letter from abroad
• Announcement to passengers
• Forum letter
• Airport posting: Abbr.
• JFK letters
• 7th Greek letter
• Symbol for viscosity
• Metal core?
• In-flight info
• In-flight announcement
• When a plane is due in: Abbr.