Virgin Australia chief John Borghetti says the airline's tie-up with budget airline Tiger Airways and acquisition of regional carrier Skywest was good for travellers and jobs.
Virgin announced on Tuesday that it was buying 60 per cent of Tiger Airlines for $35 million, and had made a $98.7 million takeover offer for Skywest.
It also announced that its alliance partner Singapore Airlines would take a 10 per cent stake in Virgin.
Mr Borghetti said the deals meant that Virgin would be in every segment of the Australian aviation market and would increase competition across all sectors.
"It's good for consumers," he told a press conference in Sydney.
"It's also very good for jobs. It stimulates demand."
All deals are subject to regulatory and shareholder approval.
If they receive the go ahead, Virgin will expand its fleet to 139 aircraft and employ more than 9,000 workers.
Under the deal with Tiger, the discount carrier will expand its capacity in Australia and have more attractive offers for customers.
Tiger and Virgin plan to spend up to $62.5 million on increasing the budget airline's fleet from 11 aircraft to 35 by 2018.
Tiger will continue to use the Tiger brand for at least another 20 years.
Tiger chief executive Koay Peng Yen said the deal with Virgin was a significant step forward for the company.
"The joint venture will bring about a stronger and more competitive Tiger Australia, and allow us to deploy more capacity and attractive budget offerings to our customers," he said.
Tiger Australia made a $20 million loss in the three months to September 30, an improvement from a $27 million loss in the same period in 2011.
Revenue grew by $53 million to $62 million.
Under its cash and scrip takeover bid for Skywest, Virgin is offering 22.5 cents in cash and 0.53 shares in Virgin Australia for each Skywest share.
Virgin said it had secured in-principle agreement from Skywest to go ahead with the offer, which is worth 46.88 cents per Skywest share.
Skywest executive chairman Jeff Chatfield said the offer, represented a substantial premium to the airline's share price and would only go ahead in the absence of a superior bid.
"Skywest will be appointing a Singaporean independent expert to advise the board on the value of the proposed consideration," he said.
"Based on our advice it is likely that this proposal will take some months to fully play out."
Meanwhile, Singapore Airlines has paid $105 million for a 10 per cent stake in Virgin Australia.
Singapore, which entered an alliance agreement with Virgin in June 2011, has acquired almost 246 million Virgin shares at 42.88 cents each.
"We believe this investment demonstrates their confidence in our strategy and it enables Virgin Australia to fast track its growth plans," Mr Borghetti said.
The deal has received approval from the Australian government's Foreign Investment Policy.