We're supposed to do a patrol mission, and even though I've checked and unchecked the tick box for the flight leader, (not sure if dark color means checked, or if light color means checked), he will never take off even after 15 to 20 real time minutes of warm up and enemy A/C peppering our field with bullets.

September 18th, 1916, Jasta 2 flying out of Velu Airfield. Again, thanks for your interest in trying to figure it out. I do appreciate it.

On your own career, do you see what I mean about the check box for assigning the flight leader? It's a little wonky, I myself would have made it so you would actually see a check mark or an x to show that it was actually checked, but that's just me. I'll just fly other careers for now, or maybe try some online action.

On your own career, do you see what I mean about the check box for assigning the flight leader?

That's not a check box but a sort of "banner" that just notes who the flight leader is.

No, if you notice, I purposely held the mouse pointer on it on the bottom picture, and it states "Assign as sortie leader." The top one shows the box being the background color, while the bottom one shows it being white or light grey. The box can be changed by clicking on it.

I may be off the mark, but if I remember correctly that little banner is just a symbol, not a check box. That symbol says that the person next to it is the sortie leader. I think the ability to assign a flight leader is reserved for the squadron commander. A more detailed interface is made available once you reach that rank in which you may assign pilots and direct who leads the flights and what aircraft they fly. I also think that the sortie leader is the farthest left plane on the airfield. (has a streamer on the wing struts). If youre the farthest left plane and you are waiting for someone else to take off then you'll wait forever because they are all waiting on you. If you are any of the other planes in order someone else should initiate the take off process on their own. Planes with an open throttle, like the EIII will just go ahead and take off once they turn their engines on regardless of flight order (have seen this in mixed flights). This is from memory, and I can't test it in the sim right now, but I think its accurate. I hope maybe this fixes your problem.

Edit: Also, in your screen shots, you are the highest ranking flier. By default you should be the flight leader.

you can only assign flight leaders as commander(boxes will appear to the left of ALL pilots for you to check). in the "settings" tab next to "begin mission" you can check a box for "warmed-up engine". in career beta, the flight leader is always on the far right. hope this helps!