A washed up celebrity in a bitter custody battle with his scheming ex-wife, is knocked unconscious by a plane crash and awakens believing he is a super hero from one his films.

Thanks for the feedback everyone. Very helpful.

Language is very important, so when I see "knocked unconscious by a plane crash", I know what you mean, but I still think "did the plane crash into him?"

Just something to look out for...

You have a good base for a story in this log line. By defining the MC as a "...washed up celebrity..." you're specifying the MC as potentially either disillusioned or deluded. This means the inner journey will be about him learning to either not be bitter about life or learn to accept reality.
The MC's journey to achieving the outer goal will need to be a metaphor for either one or the other inner journey's I mentioned above.

At this stage as mentioned by DPG and Lee Brooks, "...a bitter custody battle with his scheming ex-wife..." seams unrelated to the plot and the logline would benefit from removing it.

If you could clarify what the objective outer goal is that the MC needs to achieve and relate it to the inner journey then this could be a very interesting logline.

Hope this helps.