Is it mandatory to uses a Elite Pilot Trait?

For Example:

I have a Black Squadron Pilot with the Elite Pilot Upgrade. I want to move on”4” and Shoot on”6”. Am I restricted by the upgrade, or can I use it at will?

Depends on the upgrade.

But unless it says may as part of it, then most cases, yes you ahve to use it.

I'm guessing you mean Vet Instinct there for your example. No that's not optional, it changes the printed value of your ship from a 4 to a 6. So you have to always treat the ship as it was PS6.

I think you are referring to Veteran Insincts - this upgrade changes your Pilot Skill, it is not optional. As a rule of thumb, If an upgrade says "may" it is optional, if not it is mandatory.

There is a whole section in the FAQ about effects that modify Pilot Skill, I forget exactly what page.

Edit: ..........

No thumbs involved - it's just a rule

Page 19: Unless a card ability uses the word “may” or has the “Action:” or “Attack:” headers, then the ability is mandatory and must be followed.

Got it! Thank You!

You need to take lots of different things into consideration when choosing those upgrades. Is this upgrade going to work well with this pilot? Is it going to work once per opportunity, once per turn, or just once per game? Do I have to discard the upgrade once it's used? Many, many options to consider.