Filed under: Private equity, JPMorgan Chase (JPM), Goldman Sachs Group (GS), Morgan Stanley (MS)As Blackstone goes through the convoluted process of its own IPO, the firm is also prepping a portfolio company for the public markets: Orbitz.Back in 2003, Orbitz actually took a flier as a public company - and then sold out to Cendant in 2004. Cendant then wrapped the company into other units and formed Travelport. Then last year, Cendant sold Travelport to Blackstone.One thing's for sure: the investment banks must have racked up lots of juicy fees.Orbitz got its start in 1999. The founders included American Airlines, Continental Airlines, Delta Air Lines, Northwest Airlines and United Air Lines. Yes, the idea was to tap into the emerging online market for ticketing.Now, Orbitz has an array ...