David in Alien: Covenant

Groovy!

I think Scott is borrowing from Cameron's Skynet systems where their models are covered with biological skin that replicate and heal its self, so it can pass for human. This would explain how David would be able to reattach his head and it would heal back together, pending some help from Shaw. So it would explain the growth in hair.

In the latest movie clips i've seen, Walter looks like he's had stitches in his face so, yes I think the androids have skin that can repair itself and I assume hair that grows. 

I think it makes sense as to why David would have to Dye his Hair in Prometheus as the Viral Videos David also had Blonde Hair, and so if this is part of the Manufacture Process, and so its a Wig or similar (Synthetic Hair) he would not need to dye it.

so this shows over time Davids Hair Grows and so if his natural Hair is Brown this is why he would have had to dye his roots Blonde, and then also why he has Long Hair in this shot and how indeed once the Blonde Locks have been cut off he would be left with Short Brown Hair.

David entertained the inhabitants before destroying them:

It appears Shaw Lost Davids Head on the way and so she had to make do with borrowing one of Worzels..

For those from outside the UK who are like WTF!

Here is a piece of British Classic TV

You may recognize Jon Pertwee  better as the 3rd Dr Who from 1970-1974

Wonder if Shaw finds the Job as easy as at 25 Minutes in this Episode

BigDave That is really good! Do you watch A Bit of Fry and Laurie and That Mitchelle and Weber Look? I know they are old.

The way each android chooses to style their hair can possibly be looked at as being reflective of their individual personalities.

Is there synthetic DNA in the hair causing it to grow?  Or is it more like the Terminator series and it's real hair?  I find the fact that David's hair goes through changes very interesting.  

In the future, some of them might even be able to change their hair colors at will.  FATHER appears to prefer the blonde ones, so he may have influenced "Vickers 3" to be born a blonde.  

I have a theory that a brunette genetic sibling of Miss Vickers (who I refer to as Vickers 4) is now in control of the company. The blonde-haired version of Vickers we met in Prometheus was Peter Weyland's favorite; Capt Janek felt that "if you can't be with the one you love, love the one you're with."  MUTHUR would reveal that Vickers 1 died many years ago.  Some of the board members don't even notice that Miss Vickers changes her hair after returning from the Prometheus mission.  They think she simply dyed her hair, not that she actually died.  The details are kept classified to prevent the other board members from knowing that "Miss Vickers" should technically be dead...

@Big Dave - Worzel Gummage!!

Ive found a shot of David and Shaw's wedding!