(Crain's) — Jeff Smisek, CEO of United Continental Holdings Inc., is encountering turbulence from pilots, who plan to picket at some airports this week over the use of regional jets flown by contract carriers. It is Continental pilots who are angered that Continental will begin using 70-seat regional jets contracted by United using outside carriers for flights from some of its hubs, using contract partners, beginning in January. The airline's current contract with the Air Line Pilots Assn. prohibits Continental from outsourcing flying of jets with more than 50 seats. "This was a surprise," a spokeswoman for Continental pilots' union said of the change. United pilots also oppose additional contract flying at the airline, but United has higher limits for outsourcing, allowing regional partners to fly jets of up to 70 seats. "We disagree with ALPA's interpretation, and they have agreed with our suggestion that we quickly resolve this through expedited arbitration," an airline spokeswoman says.