The International Air Transport Association (IATA) expressed concern that a premature return to pre-pandemic slot use rules in the EU this winter risks continuing disruptions.
The announcement comes as the European Commission has announced it intends to return to the longstanding 80-20 slot use rule, which requires airlines to operate at least 80% of every planned slot sequence.
IATA noted that the global slot rules are an effective system for managing access to and the use of scarce capacity at airports.
"The system has stood the test of time and while airlines are keen to restart services, the failure of several key airports to accommodate demand, coupled with increasing air traffic control delays, means a premature return to the 80-20 rule could lead to further passenger disruption," the organization warned.
IATA said the evidence so far this summer has not been encouraging.
It said airports had the 2022 summer season schedules and final slot holdings in January and didn't evaluate how to manage this in time.
It further noted that airports declaring that full capacity is available and then requiring airlines to make cuts this summer shows the system is not ready for reviving "normal" slot use this winter season (which begins at end of October).
"The chaos we have seen at certain airports this summer has occurred with a slot use threshold of 64%. We are worried that airports will not be ready in time to service an 80% threshold by the end of October," said Willie Walsh, IATA's Director General.
"It is essential the Member States and Parliament adjust the Commission's proposal to a realistic level and permit flexibility to the slot use rules. Airports are equal partners in the slot process, let them demonstrate their ability to declare and manage their capacity accurately and competently and then restore the slot use next summer," Walsh added.
