TIE Strikers

It's a trap
On Scarif, the prototype fighters are release once Krennic issues all the defended of the base to attack.

Atmospheric Defenses.
The TIE/sk x1 prototype air superiority vehicle was developed by the weapon development on Scarif. It doesn't operate well in atmospheres, but it will always prevail in a dogfight, as shown by the death of Blue Leader