Stephen Hannahs, the cofounder and former chief executive of Newport Beach-based Aviation Capital Group Corp., has partnered with a New York investment firm to launch Wings Capital Partners, a boutique investment firm.

Wings Capital will focus on advisory and financing services, as well as aircraft purchases, according to the firm.

Hannahs said the partnership with Two Sigma Private Investments LLC is expected to bring the new venture "a unique form of flexible capital."

Hannahs in 1989 cofounded Aviation Capital Group, which eventually became a wholly owned subsidiary of Pacific Mutual Holding Co. in Newport Beach. Pacific Mutual operates through its Pacific Life Insurance Co. unit and is the largest private company based in Orange County, with $7.25 billion in 2012 revenue.

Hannahs oversaw Aviation Capital as chief executive since its inception through the end of last year, when he retired. Aviation Capital has grown to be one of the largest aircraft lessors worldwide, with about $8 billion in assets and a portfolio of more than 250 airplanes, as well as 90 or so airlines as customers.

Hannahs remains on Aviation Capital's board of directors.