New proposals have been put forward to tighten the definition of parent carrier under the planned revision of the CRS Code of Conduct by the European Commission.
The proposed changes define a parent carrier not just as an airline or rail transport operator which owns or effectively controls a CRS.
It extends the definition to one which includes an airline or train operator which "participates in the capital, effectively controls, or has the legal right to nominate any executive or any member of the board of directors, supervisory board or other governing body."
In an additional amendment to the EC's revised, says that details of any capital holding by an airline or trail operator in a CRS or any stake of a CRS in a carrier or rail operator "shall be publicly disclosed."
The changes have been proposed by Timothy Kirkhope, a lawyer and UK Conservative MEP appointed as "rapporteur" on the CRS code to the European Parliament's transport and tourism committee.
The proposed changes will go before the committee next week.
When the EC produced its revised code of conduct for CRSs in Europe last year, it included safeguards to prevent possible abuse by airlines defined as parent carriers of CRSs.
These were airlines which owned or effectively controlled CRSs.
But the Commission then said it did not regard Air France, Iberia and Lufthansa which together own more that 46% of Amadeus, the largest CRS in Europe, as parent carriers.
Mr Kirkhope, in his report to the committee, rejects this stance, calling the parts of the EC revised code on parent carriers as "unsatisfactory."
"The parent carrier definition is misleading," he said.
He said that the three airlines say their stake in Amadeus is "simply a financial investment."
But he says it is "legitimate" to conclude that it has more to do with "competition gains" which he describes as preferential conditions.
Mr Kirkhope adds: "The risk of abuse is particularly high when a dominant airline participates in a dominant CRS (e.g. which is the case in the French, German and Spanish markets).
"Your rapporteur believes this should be clarified and the definition tightened."
The Business Travel Coalition (BTC) has sent a letter signed by more than 100 travel organisations to the committee.
It says the refusal to name Air France, Iberia and Lufthansa as parent carriers has made its safeguards under the revised code "toothless."
It adds: "In ways that before were patently unlawful, the three Amadeus owners are now free to discriminate in favour of Amadeus, and Amadeus is free to discriminate in favour of its three owning airlines.
"The upshot is that travellers all across the EU are now staring directly into the abyss of higher fares, less choice and poorer service.
"Parliament has the opportunity to correct the parent carrier loophole created by the Commission to avoid detrimental effects for travellers across the EU."
* see BTE Analysis