Nine out of every 10 scheduled take-off and landing slots at Sydney Airport were operated during the six months to 28 March, with overall slot utilisation reaching 95 per cent once approved cancellations were taken into account.
New figures released by slot manager ACL Asia Pacific in its Northern Winter 2025 (NW25) end-of-season report reveal Sydney’s prized slots are being used at some of the highest levels on record, highlighting the ongoing demand for access to Australia’s busiest airport.
The 95 per cent utilisation rate comprises 90 per cent of allocated slots that were flown and a further 5 per cent cancelled due to circumstances beyond airlines’ control, including war and adverse weather.
Sydney’s biggest operators, Jetstar, Virgin Australia and Qantas, used almost all of their allocated slots during the period, allowing them to retain their usage rights for the Northern Winter 2026 schedule, which begins in late October.
The report marks the first time detailed slot usage data has been publicly released for a major international airport, following efforts by the Australian Government to increase transparency around slot allocation and enforcement at Sydney Airport.
Some international airlines faced significant operational challenges during the reporting period, particularly as conflict in the Middle East disrupted air travel. The US-Israel war with Iran led to airspace closures across the United Arab Emirates, Qatar and other parts of the region, affecting several carriers operating to Sydney.
As a result, airlines including Emirates, Etihad Airways, Qatar Airways, Qantas and Virgin Australia were granted slot usage dispensations, enabling them to retain unused slots for future seasons.
Maintaining automatic rights
Under Sydney Airport’s slot regime, airlines must comply with the 80:20 “use it or lose it” rule, which requires carriers to operate at least 80 per cent of their allocated slots to maintain automatic rights to those slots in future scheduling periods.
While most airlines comfortably exceeded the threshold and recorded retention rates above 95 per cent, several carriers fell well short. Tianjin Airlines retained just 33 per cent of its slots, while Hong Kong Airlines retained 71 per cent and China Eastern Airlines 76 per cent.
The report also highlighted ongoing punctuality challenges across the airport network.
More than a quarter of all operated flights missed their allocated slot window, which is defined as a 15- or 30-minute period for take-off or landing depending on route length.
International carriers performed better than domestic operators, with 83 per cent of international flights operating within their allocated slot window compared to 72 per cent for domestic services.
According to ACL, the most common cause of slot misses was aircraft arriving late from previous sectors, creating consequential delays throughout the network.
“Airports need confidence that every available movement is being used effectively. ACL’s approach delivers strong utilisation and operational performance while preserving capacity for future growth – a key priority for airports across Australia,” said ACL Asia Pacific Coordination Manager Darren Batty.
“At Sydney, we continuously refine how slots are used – aligning schedules, clearing waitlists and responding to operational changes in collaboration with airlines, Sydney Airport and Airservices Australia to deliver strong utilisation and ensure the system remains responsive to demand so that there’s still available capacity for airline expansion.”
Click here for the full report: Northern Winter 2025 end of season report.
