Uzzi_

As Lady_Tormenter says you can have upto 4 of these power pools. At some later stage you will need a travel power as you find missions will be more difficult to get to.

So if you want Invisibility and Flight, then by all means take the Flight and Concealment power pools. You need to select one of the two powers available in each pool to have access to the third power (which becomes available at level 14)

Suggestionwise, try to get Fly at level 14, which means you need to select either Air Superiority or Hover before this stage (very latest level is 12). From the concealment pool, the first Hide power is okish, Grant Invisibility would probably be the better choice to help an ally. Then later on you can have the better Invisibility power.

I would say your main priority would be Focused Fighting/Senses, though they are toggles, but provide your main defence for most of your levels in comparison to your passive skills.

Agile and Dodge are nice to have and are useful, would personally leave them unslotted, but it's your choice at the end of the day.

Happy scrapping.