US, Oct. 27 -- An eTurboNews investigative opinion on the codeshare loophole that can leave loyal airline customers without the privileges they believed they were purchasing.

A Lufthansa ticket, a Lufthansa flight number, a confirmed connection through Frankfurt and United Airlines Premier 1K status should sound like a straightforward Star Alliance journey. Yet a recent Berlin-Malta round trip exposed a surprising divide between the airline selling the journey and the airline actually operating it. The result: reported denial of lounge access, missing priority services, baggage confusion and no United MileagePlus credit.

The issue reaches beyond one dissatisfied frequent flyer. It raises a question about airline loyalty programs: when ...