Troubled US Airways and America West Airlines completed their merger on Tuesday, creating the sixth-biggest US airline in terms of passenger miles.
The combined airline will fly under the US Airways flag
The combined airline, will be dominated by America West but called US Airways, and hopes to compete with budget rivals Southwest Airlines and JetBlue.
"Today we start a new chapter in aviation history," said Douglas Parker, America West chief executive.
US Airways has had to seek bankruptcy protection twice in two years.
The airline, which has just completed a one-year restructuring programme, said the merged company would have $2.5bn (£1.38bn) in cash at its fingertips.
US Airways and America West were the seventh and eighth-largest airlines in the US before the merger.
The new airline faces continued high fuel prices and the problems of merging the two workforces over coming years. The airline will employ nearly 40,000 people.
The difficult conditions have led two of the largest US airlines, Delta and Northwest, to recently seek bankruptcy protection.
US Airways begins trading on the New York Stock Exchange under the ticker symbol LCC.