The bank is in early stages of putting together an offer and is exploring a number of options, which include making a direct offer or putting together a consortium to bid for the assets, a source told City A.M.
RBS Aviation is one of the world’s top four commercial airline leasing firms with over 200 aircraft currently on lease. It has a portfolio value of $8bn (£4.8bn).
Royal Bank of Scotland previously tried to find a buyer in 2009, but shelved the sale last year as the financial crisis made bids unattractive. Goldman Sachs has been recruited to handle the auction.
The first round of bids from interested parties are due on Friday this week.
A source close to the company said the unit had attracted interest from several companies across the world, including private equity firms and financial institutions.
Dublin-based RBS Aviation said it “will not be commenting further during the sales process”.
Last year, Macquarie expanded its aircraft leasing business by buying up American International Group’s aircraft portfolio for $1.6bn.