Acquiring the RBS fleet of more than 200 aircraft would catapault Macquarie to become the world's third-largest aircraft lessor behind General Electric and American International Group, the newspaper reported. Last year Macquarie became a serious player in the jet industry when it bought 53 passenger jets from AIG for nearly $2 billion.

China Development Bank, Wells Fargo and Sumitomo Corp are also reportedly in the final round of bidding.

Underwriter Goldman Sachs is expected to oversee negotiations with two final parties and bids have come in towards the lower end of a $6 billion to $8 billion range, said the report. 

RBS has been obliged to sell off a number of its non-core assets since it was rescued by the UK government following the 2008 financial crisis, which nearly brought the bank to its knees. RBS, which is still 83 per cent owned by the UK tax payer, has been looking to sell assets including some of its art collection, insurance business and other parts of the bank.

RBS Aviation is one of the world's top five commercial airline leasing firms. It owns, manages or has orders for 335 commercial jet aircraft according to its website, and could fetch between $6 billion and $8 billion, reports have said.