I've picked up Freddy and while not the best iv'e had some great matches and am versatile. Sektor in general is tough because he has teleport and if you make a single mistake goodbye 50% of your health. The best you can do is when he is open f4,2,1, mid spike, far, spike, SD for frame trap. Then hit him with another far spike and if he falls for it SD again, but don't get too predictable with the far spike he will teleport your head off. As far as air to air I do the JP into dash into f4,2,1 mid spike, far spike, SD and if i'm feeling frisky as I always am against Sektor I got for a 50/50 combo start either his b1,1 or b2 into an EX spike, JIP combo his head off.
Also if your oppenent doesn't have TP they are almost always forced to jump forward due to Glove Toss which pushes back and from full screen can kill almost all if not all armored moved like nomad dash and sub's ex slide. When they jump forward just mid spike, far spike, SD or mid spike, SD ( I do that because for someone reason I can't get the timing on two spike oddly enough) but anyways they move back to the same spot and are frame trapped again by SD etc...
Anyways, i'm still new to Freddy so it is possible that some other stuff is better, but this works for me