Got on my flight and the cabin is hot. No air flowing from the overhead vents. Pilot and co-cpilot are not onboard yet to turn the air on. There's another UA pilot in uniform sitting on the aisle seat one row in front of me. Flight attendant asks him if he can go to the cockpit and turn on the air. He replies, "I'm not a 73 guy and it would be in appropriate for me to do that". Maybe there are rules preventing him from touching anything in the cockpit if he's not assigned that flight. But if not, he's response seemed kind of lame. So we baked another 10 minutes until the pilot arrived.