The CarTrawler Ancillary Revenue Yearbook by IdeaWorks Company has been released in full and includes, for the first time, a look at each of the airline's relationships with Amadeus, Travelport and Sabre.

Highlights were released a few months ago, concentrating on the top 10 carriers, with the 105-page report drilling deep into 67 airlines' financial filings for 2015.

Each airline gets its own entry in a consistent format, of which "A la carte services sold via the GDSs" is one of the fields.

IdeaWorks' methodology is clearly outlined in the report, and it takes great care to define not only what it means by a la carte services (there are nine different services which could come under its definition) but also how it got the info from the GDSs (Amadeus and Sabre did the legwork for IdeaWorks while the Travelport's data came from its website).

Even with exclusions and caveats there are some revealing differences between the three.

But the biggest airline/GDS story of the past year or so is Lufthansa Group's  "distribution cost charge" which added €16 fee to every ticket booked via the GDS. The move was announced in June 2015 and implemented in September that year, giving it a limited impact on the period covering by IdeaWorks.

The group's entry in the report shows the extent to which it uses the GDSs for its a la carte ancillary revenue generation.

IdeaWorks notes that the charge "could qualify as ancillary revenue but has not been added to the results because estimates could not be made. "

Lufthansa Group took just shy of $1.5 billion in total ancillary revenues in 2015,  5.5% of total revenues or $13.87 per passenger.

Elsewhere, three Chinese airlines are among the 67 analysed: China Eastern, China Southern and Spring Airlines. China Southern sells baggage allowance via Sabre and is the only one of the three using a GDS.

IdeaWorks has been producing similar reports for eight years now, which gives an historical perspective from the airlines' point of view. Bringing GDS agreements into the mix squares the circle by framing the relationship between the airlines and their tech suppliers.

The full study is available free of charge via the CarTrawler website. Related reading from Tnooz: Lufthansa distribution goal at least two years away (Sept 2016) Top airlines now earning more than a third of revenue from add-on services (July 2016) Where airline execs think ancillaries are heading (June16)