Dreaming that I'm lucid dreaming with dream control? What.

I've been able to control my dreams since I was a child. So I've been able to experiment a lot, and develop this skill.
Quite often my nightmares act as a stimulus into reaching a lucid state. And I've never had a problem with dream control once lucid. But lately, I'll have a nightmare, and I'll become lucid (or so I think.) I'll attempt dream control, and it will seem to work, accept it actually doesn't. I'm horrible at explaining things.

For example. A nightmare I had a few weeks ago:
I was walking to my car in a dark, abandoned parking lot at night. A few men approached me, grabbed me, and tried forcing me into their truck. I became lucid, gained dream control, and flew away. (Usually at this point, I can use dream control to change the entire environment and direction of the dream. Make the darkness transform into light, make my enemies my friends, et cetera.) Once I flew away, I tried changing the scene of the dream. But before I got to it, one of the men began flying after me. Caught off guard, I tried to use dream control to stop his ability to fly. But it failed horribly.

The nightmare just continued until I woke up. It felt as if I had never had dream control at all, and maybe hadn't even reached lucidity. Is is possible to dream you have dream control? Or am I losing control of my abilities?

This isn't a problem with your dream control, this is a problem with how you handle nightmares. Running away is what an non-lucid dreamer would do. Some that are new to lucid dreaming often try to battle or escape nightmares using the power of dream control. But what you are supposed to actually do is face the nightmare, and ask it what fear or issue it represents. If the nightmare does not respond and cannot reveal this information to you, then you fight it. And you will win. Because if a nightmare has no purpose for existence, it becomes weaker and much easier to defeat.

I once asked a giant evil monster what it was supposed to represent and it turned into a kitten.

Control =/= lucidity.

And you could fly, so the control is there. I will agree with JadeGreen that you are doing this the wrong way, there might be a reason why it just won't vanish and you may want to check out why.
However if you don't want to, just go into a more agressive approach and roast them! I generally eat pesky DCs or blow them into oblivion. Same for nightmares, which generally solves the problem permanently too.

I haven't tried asking what the fear or issue represents. I've always wanted to.
I've definitely noticed my habit in nightmares is running away. It seems to be so automatic that I don't consider other options.
More recently I've fought back. Hm. Thanks for the advice, though. I feel like this could really be an enlightening dream experience.

fear is the worse thing you can allow into your heart and mind while lucid, for fear effects your confidence, and confidence effects your abilities