Stealth fighters have only one of the two main uses of jet fighters, but they do it better than jet fighters. Jet fighters defend your cities with air superiority, something stealth fighters can't do for some inexplicable reason. They also defend your bombers by drawing out and engaging your enemy's defending fighters. You have a better chance of winning with a stealth fighter.
So if your enemy has an air force, you need at least four fighters in your stack of bombers to be relatively safe. Two fly air superiority to protect your city/carrier group and the other two to probe the enemy defenses. If one gets shot down, they don't have a chance to take it off air superiority and fortify it on your turn, so your second fighter will in that case get to blast a weakened enemy.
So if your enemy has an air force, you need at least four fighters in your stack of bombers to be relatively safe. Two fly air superiority to protect your city/carrier group and the other two to probe the enemy defenses. If one gets shot down, they don't have a chance to take it off air superiority and fortify it on your turn, so your second fighter will in that case get to blast a weakened enemy.