A majority of shareholders approved the sale of Midwest Airlines' parent at a special meeting in the company's hometown of Milwaukee.
The sale is still under antitrust scrutiny because the deal includes rival Northwest Airlines as a passive investor. The Eagan, Minnesota-based airline is a major operator at Mitchell International Airport, Midwest's base.
Midwest executives say they're confident the sale will be approved by federal regulators.
Shareholder approval follows months of escalating offers from rival AirTran Holdings, the Florida based operator of AirTran Airways.
Midwest agreed in August to be bought out by TPG for $17 a share in cash after rebuffing AirTran's offers. Midwest hopes a deal with TPG will preserve its brand and heritage.