In the long term, your ground game is only as good as your antiair. Take that lesson from SFxT if nothing else.
So no, “just blocking” is a bad idea. But keeping yourself out of the dangerous ranges would help. If worst comes to worst, you can take a strategy of reacting to crossups with command dash, which low-profiles the jump-in and brings you to safety, at expense of positioning.
Standing jab is very good against close jumps, but has to be done late. That’s both a negative and a positive though - it means you can do it late and still succeed. Realizing that this normal existed reduced my anti-air worries by a lot.
At slightly further range from ideal jab AA range, standing fierce would clean-hit just about everything even from Zangief’s various jump-in options. But the range where this is the best AA is fairly small.
At these two ranges, jump back MP is probably her best air-to-air button. Jump jab is slightly faster and the hitbox is aimed upwards, which may be a bad or a good thing. Jump MK/RH had more range but also worse hurtboxes.
For further ranges than that, extending into max-range jump-ins, low fierce tended to be a steady option. Although you could catch some of those long-range j.RH with oddball things like s.MK, I wouldn’t rely on it.
If you’re ready to use it, probably the best AA for max-range jump-ins is instant launcher because it also works against empty jumps. EX launcher will also work and give you juggles, which is a nice way to call out people who are trying to bait a low fierce with an empty jump, or people who neutral jump trying to catch you doing something.
I don’t really like using EX reversal for an anti-air because other options will usually work, and it’s not any better against crossups than the fierce buttons are (whiffs often), but it is the most reliable way to deal with divekicks, and it’s also the only thing that’s going to work if you’re too late with your reaction to get a normal AA out in time.