Australian airline company Virgin Blue requested the U.S. Department of Transportation for a three-week extension for submitting its argument.

The extension will give the airliner until October 13 to prepare a complete and detailed response to the issues raised by the transport department. Virgin Blue and its potential partner Delta Air Lines were first given two weeks for the response.

On Tuesday, Virgin chief executive John Borghetti expressed optimism on the proposed alliance. The airliner's head was confident that the US regulators would decide for the partnership across the Pacific.

The U.S. transport regulator, in its tentative decision, considered both potential partners as new to the U.S. - Australia market. The department also considered both airliners as not yet capable of delivering the benefits outlined in the proposal.

Borghetti, however, insisted the Air New Zealand and Delta alliances, as well as a third deal with Abu Dhabi-based Etihad, would be highly beneficial to the traveling public.

Virgin Blue is also dealing with the preliminary decision of the Australian Consumer and Competition Commission (ACCC). The consumer regulator has initially rejected the proposed trans-Tasman alliance with Air New Zealand.

The airliner is also set to convince the ACCC to find merit in the proposed alliance.