When United filed for bankruptcy in 2002, she played a key role coordinating the case, ensuring it was well positioned to exit in 2006. A year later, as head of investor relations, she skillfully positioned United to the business community.
In 2008, Mikells was named CFO. Hammered by rising oil prices and the global recession, United needed cash. She negotiated asset sales, stock offerings, and secured loans; kept in compliance with loan covenants; constrained spending; and retired and sold surplus aircraft - accomplishments that enabled United to ride out the storm. In addition to being CFO, she also was appointed executive vice president in 2009. By the time United agreed to merge with Continental Airlines in May of 2010, she already had fans on Wall Street for her work strengthening the firm's financial position and raising more than $4 billion in liquidity.