Related Clues:

• ORD or LAX figs.
• Info from airlines
• They're marked on some math tests
• Cockpit announcements, briefly
• Letters from Plato
• Announcements at LAX
• Expected landing hrs.
• Logan info
• Letters before xi's
• Greek letters after mus
• In-flight figs.
• Greek T's
• Followers of zetas
• Socratic vowels
• Stats for 52-Across