So during my next game i want to explore ship fighting

The party have a wayfarer ship and 2 x wing the mission is to rescue an npc in a prison the group will have 3 air support and two on ground to jail break the guy out.

The jailbreak is not my problem.

My problem is ship battle with a wayfarer and two xwing what would be the go ratio of tie fighter and other imperial ship. I dont want to overwhelm them and have an auto game over. But want a challenge to bring fear and stress on what they need to do or else they will die

Instead of a battle (which I don't really like these rules for) I'd suggest a chase punctuated by shooting (which I really like these rules for). It's hard to scale things in this game. It's not like X-Wing, where you can pretty much get a balanced game if you have equal points. As an example, some people found the end fight in the EotE beginner game to be too easy; but a lot of people, including myself, found the players one hit from doom.

Giving the players a running goal means it doesn't come down to losing a ship, but rather minimizing damage. Since each hull point costs 500cr to fix, that can be enough right there to cause fear and stress, never mind if the Imperials get a critical hit and destroy some component.

Try a pair of TIE Fighters and see how they fare.

What weapons and shield capability does your Wayfarer possess?

You might want to test the waters by letting run an encounter with them using a pair of Y-Wings backed up by say a Corellian Corvette against a group of 4 TIE's and maybe just maybe a smaller Imperial ship able to carry those fighters like for example a Gozanti from the Star Wars Rebels series if that's available.

The idea is that this will give them a heads up on what to expect as well as an introduction to their later mission to help rescue whoever survives that introduction.

The above is so you get an idea what to expect when they get to use their X-Wings and more importantly avoid the possibility of a whitewash because you didn't forsee those TIes being that powerful.

Well it is just a suggestion.

You could go with a Marauder Class Assault Corvette and a handful of TIEs(maybe 2 groups of 3)

The Marauder is technically a capital sized ship, and mounts the weaponry to match, but its not all that much more durable than the Wayfarer. It also states it has capacity for 12 fighters, which is about as low as you get stock.

Assuming your group's wayfarer has a couple weapons above the stock model, which only has the 1 forward quad laser cannon. If they don't have any additional weapons they'd be kinda screwed no matter what you toss at them.

2 words: reinforcements.

Pit them against 2 minion groups of 3 TIEs each. If they start to burn through them, bring in 2 or 3 more groups.

Thank you all for your suggestion/help