Historical clue formulations

• U.K. carrier, once — 2011-07-31
• Old U.K. carrier — 2011-02-23
• Airline mentioned in "Back in the U.S.S.R." — 2009-08-16
• Onetime airline — 1997-11-19
• Former Eur. carrier — 1997-07-06
• Former Eur. airline — 1997-05-18
• Bygone airline — 1995-01-04
• Whilom airline inits. — 1994-07-01