Ride-hailing app Uber has lost another round in its battle with some drivers who filed a class-action lawsuit against it.

In August, US District Judge Edward Chen ruled that drivers should be allowed to form a class. Uber appealed that ruling straight to the US Court of Appeals for the 9th Circuit, but in a decision handed down yesterday, the appeals court declined to take up the case. The ruling doesn't mean that Uber can't challenge Chen's class certification at a later time, but the company will first have to fully litigate its case.

That means that Uber may well have to make its case to a jury in Chen's courtroom. He has scheduled a trial for June 2016, according to a report in Reuters. "We look forward to presenting the facts about how drivers use Uber with complete flexibility and control over their work to a jury," Uber attorney Theodore Boutrous told the news service.

It's not clear how many Uber drivers may have to drop out of the class, however, due to an arbitration clause added in June 2014.

According to Uber, drivers who continued to drive after June 2014 and did not opt out of the arbitration deal shouldn't be eligible to join the class. In Uber's view, only a small percentage of the 160,000 people who have driven for Uber in California will ultimately be eligible. Both sides are briefing their views on the arbitration issue before Chen.

If drivers win the O'Connor v. Uber case, then Uber may be required to reimburse things like gas and maintenance expenses. The company may also incur additional expenses, such as needing to pay workers' compensation insurance, if drivers can no longer be independent contractors.

Uber is the largest of many tech companies sometimes referred to as part of the "gig economy" or "sharing economy," and other companies have faced their own legal challenges on the issue of whether workers should be considered employees or contractors. The same lead lawyer representing the O'Connor plaintiffs has sued SF-based startups DoorDash and GrubHub, as well as Massachusetts-based Handy, over alleged labor violations.