A one-way trip to the airport from the CBD costs almost $17 when using an Opal card. Credit:Steven Siewert This is particularly so after congestion on roads in and around the airport worsened recently, which Roads Minister Duncan Gay told a business conference on Wednesday "could only be described in technical terms as a bloody mess". The fact that the government is reaping windfall dividends from passengers travelling to the airport stations – more than $1 million a week – challenges a common view that the Airport Link Company is the major beneficiary from the expensive fares. Transport Minister Andrew Constance said any funds the government received from the Airport Link contract were "put back to improved transport services or better infrastructure". At present, a one-way trip to or from the airport costs an adult passenger $16.78 when using an Opal card during peak travel periods. That comprises a $3.38 fare and a station access fee of $13.40 for the airport terminals.

For those using a paper ticket, a single trip costs $17.40 – or $34.80 return. However, the station access fee is capped at $25 a week for Opal card holders who travel by train to the airport more than once a week. This measure followed a parliamentary inquiry in 2014. The latest company documents show Airport Link paid the government almost $54 million in the year to last June, up from $27.2 million in 2013-14. Since a "threshold" was reached in July 2014, the government has been entitled to 85 per cent of the sales revenue from Airport Link under a revised contract. Airport Link has forecast train patronage to grow by about 7 per cent this year, which means the "train service fee" revenue is set to be even higher this year for the government.

EcoTransit spokesman Colin Schroder said the public transport advocacy group was strongly in favour of the government using the money from Airport Link to reduce or eliminate the station access fee, or buy out the company. "The pay off for the public from that would be massive. It would reduce road traffic in the vicinity of the airport massively ... and address many of the traffic problems in the south west," he said. Sydney Airport has also supported a reduction in the $13.40 station access fee over the years. More people have been opting for the train partly because of worsening congestion on roads around the airport. The government stepped in last month to allay concerns when it announced immediate measures to prevent gridlock. At the time, Mr Gay urged travellers to consider taking the train between the CBD and the airport because it was "certainly cheaper" than a taxi or parking.

The number of people taking the train to the airport rose 223 per cent to almost 7 million between 2004 and 2014, the most recent figures from Transport for NSW show. In 2011, the Keneally government decided to subsidise the station access fees at the two non-airport stations on the line at Mascot and Green Square, leading to a surge in surge in patronage. Passenger numbers are expected to increase further in the coming years as apartment towers are built near both stations. Green Square will become one of the most densely populated suburbs in Australia within the next decade. In 2014, a cross-bench parliamentary committee advised the government to cut the cost of travelling to the international and domestic terminals by train for families or groups of people, as well as workers at the airport. Later that year the then Transport Minister Gladys Berejikilian announced that Opal card holders who travel by train to the airport more than once a week would get a weekly cap on the station fee.