The debate between Transport Minister Anthony Albanese and Sydney Airport authorities over the reason behind plane delays continues.

Sydney Airport officials insisted at the annual stockholders meeting on Thursday that there is no need to build a second gateway in the city because 39 per cent of the landing slots were not used.

However, a stockholder questioned Mr Moore-Wilton's claim of unused landing slots. The shareholders said the unused slots were off peak hours which is when people do not want to travel.

Max Moore-Wilton, chairman of the airport, blamed instead government restrictions such as the 80 aircraft movements per hour cap as the reason behind the jet departure and arrival delays.

To further pressure Sydney Airport to build a second gateway, Mr Albanese ask it to turn over an updated version of its master plan for 2013 a year ahead of schedule.

Sydney Airport insisted it can meet higher demand for capacity until 2049 in its planned changes which would involve moving Virgin operations to the international terminal and Qantas's to the domestic.

Mr Moore-Wilson stressed that the construction of a second airport is only one of 10 recommendations made by a recent joint study into Sydney's aviation needs, but he said Mr Albanese ignored the nine other recommendations.

Politics was also cited by union members of Qantas who called on more than 40 MPs from the Labor Party, Greens, Liberals and independents to warn them of the threat to Australian aviation industry's future if skills are lost to overseas competitors.

"If Qantas closes one of its bases, as it looks like it will do, we'll lose hundreds of jobs and also hundreds of future apprentices. When things change, and we need an engineering sector, it'll be too late because once these skills and the infrastructure is gone, they'll be gone forever," AMWU delegate Glenn Wilcox said in a statement.

Qantas engineers are opposed to alleged Qantas plans not to grow engineering by pursuing third part work or commit to the B787 or A380 future maintenance. The union asked the flag carrier to have maintenance work on Qantas-owned Jetstar be done on shore instead of the current practice of at least 50 per cent performed offshore.

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