Kirkland & Ellis is set to reap millions of pounds in fees after landing the lead advisory role to United Airlines, which last week became the biggest Chapter 11 filing in airline history

The work-out of the Chicago-based airline that has floundered under $5.2bn (£3.3bn) of debt, is expected to be a drawn out process that experts predict could last for at least two years.

Unlike other airlines that have restructured under Chapter 11, due to opposition from a heavyweight union-ised contingent within the company, United has sold off little or no assets in an attempt to stem its debt.

The complexity of the restructure will mean a fee bonanza for Kirkland & Ellis, which has a longstanding relationship with United.

Lead partner on the deal James Sprayregen, a highly-rated restructuring, workout and bankruptcy specialist has had a good deal of experience in the airline sector. Sprayregen was responsible for steering TWA through Chapter 11 in 2001. TWA eventually sold its assets to American Airlines.

It is believed that United’s filing is the eleventh time an airline has been forced into Chapter 11 since the sector was deregulated in 1978.